Plaintiff appeals as of right a decision of the trial court holding that plaintiff had failed to establish defendant’s paternity by a preponderance of the evidence. Plaintiffs child was born April 4, 1979, and the paternity hearing was conducted on April 15, 1982.

Prior to the hearing, plaintiff moved for the admission of the results of Human Leukocyte Antigen (HLA) blood tests indicating a 91% probability that defendant was the father of plaintiffs *762child. The trial court denied plaintiff's request under MCL 722.716(d); MSA 25.496(d), which, at the time of the hearing, prohibited the admission of all blood test results to show inclusion of a defendant in the class of potential fathers. See also Klein v Franks, 111 Mich App 316; 314 NW2d 602 (1981); Cardenas v Chavez, 103 Mich App 646; 303 NW2d 3 (1980), lv den 414 Mich 928 (1982).

Effective five days after the hearing, however, on April 20, 1982, MCL 722.716; MSA 25.496 was amended as follows:

"(4) The result of a blood or tissue typing test, and if a determination of exclusion of paternity cannot be made, a calculation of the probability of paternity made by a person the court determines is qualified as an examiner of blood or tissue types based on the result of a blood or tissue typing test shall be admissible in evidence in the trial of the case.”

Plaintiff argues on appeal that under the rules regarding retroactive application of amended statutes, she must be granted a new hearing in order to introduce evidence of the HLA blood test results. We disagree.

While we recognize that statutes pertaining to procedural matters are generally given retroactive effect, the rule of retroactivity does not require remand solely because a relevant procedural statute is amended after the conclusion of trial. The cases cited by plaintiff in support of remand can be distinguished on this ground. In Tulkku v Mackworth Rees Div of Avis Industries, Inc (On Remand), 101 Mich App 709; 301 NW2d 46 (1980), lv den 411 Mich 897 (1981), this Court held that a new products liability statute should apply to an action remanded for new trial by the Supreme Court on another, unrelated issue. In McAvoy v *763HB Sherman Co, 401 Mich 419; 258 NW2d 414 (1977), and in Sherberneau v Metropolitan Life Ins Co, 44 Mich App 339; 205 NW2d 213 (1973), retroactive application of a statute was an issue below. In Denham v Bedford, 407 Mich 517; 287 NW2d 168 (1980), and in Selk v Detroit Plastic Products, 120 Mich App 135; 328 NW2d 15 (1982), one party challenged the retroactive application of a statute which, it was argued, had an effect on some substantive right. The Courts in these cases found that the challenged statute affected only a remedial or procedural right and was therefore to be retroactively applied. None of the above cases stand for the proposition that post-trial amendments to procedural statutes automatically require remand for a new trial.

In this case, neither party challenged the validity of the statute at trial nor did the trial court erroneously construe or apply it. We thus hold that the trial court did not err in excluding evidence of the defendant’s blood type at trial and we decline to remand on the basis of the amended statute alone.

Because we find no need to remand for a new hearing, we decline to address the technically moot issue of whether defendant’s failure to answer plaintiffs interrogatories precludes him from testifying at trial. GCR 1963, 302.2(1). Defendant did not answer plaintiffs interrogatories but neither did he testify at trial.

Finally, we cannot say that the trial court’s findings leave us with the definite and firm conviction that a mistake has been committed. Tuttle v Dep’t of State Highways, 397 Mich 44, 46; 243 NW2d 244 (1976); Precopio v Detroit, 415 Mich 457, 462; 330 NW2d 802 (1982). Defendant’s mother testified at the hearing that plaintiff had *764admitted on at least two occasions that she was uncertain of whether defendant or another man was the father of her son. Matters of witness credibility are best left for the trier of fact. GCR 1963, 517.1.

Affirmed.

(dissenting). I dissent since I believe that the statute permitting the admission of the results of the HLA blood test applies retroactively; because I do not believe plaintiffs counsel waived the admissibility of the results of the test under the circumstances of this case; and because I believe that the ruling by the trial court regarding the defendant’s refusal to answer interrogatories was incorrect.

I. Retroactivity of Amendments to MCL 722.716; MSA 25.496

Were it not for the procedural nature of the issues in this case, there would be little question as to the results on appeal. There was substantial evidence both in favor of and against paternity. The trial judge ruled in favor of defendant and his ruling is not against the great weight of the evidence admitted at trial. However, the HLA blood test which showed a 91% probability that defendant is the father was excluded and I believe that, if the test results had been admitted, those results might have had substantial influence on the court’s opinion.

At the time of trial, MCL 722.716(d); MSA 25.496(d) prohibited the admission of all blood test results as probative evidence of paternity. Test results could be admitted only if they excluded a *765putative father from consideration. The HLA blood test is a blood test within the meaning of this statute. Klein v Franks, 111 Mich App 316; 314 NW2d 602 (1981). As indicated in the majority opinion, the statute has since been amended, i.e., five days after trial.

As a general rule, statutes are only to be given prospective effect unless the Legislature indicates a contrary intent. Tulkku v Mackworth Rees Division of Avis Industries, Inc (On Remand), 101 Mich App 709, 717; 301 NW2d 46 (1980), lv den 411 Mich 897 (1981). The rule, however, is subject to various exceptions. A statute may be given retroactive effect if it relates to procedure, McAvoy v H B Sherman Co, 401 Mich 419, 459; 258 NW2d 414 (1977), changes only a remedy, Denham v Bedford, 407 Mich 517, 529; 287 NW2d 168 (1980); Bannan v Saginaw, 120 Mich App 307; 328 NW2d 35 (1982); Selk v Detroit Plastic Products, 120 Mich App 135; 328 NW2d 15 (1982), or deals with a rule of evidence, Tulkku, supra, p 717; Sherberneau v Metropolitan Life Ins Co, 44 Mich App 339, 344; 205 NW2d 213 (1973). The amendment to MCL 722.716(b); MSA 25.496(d) falls into the final exception. It provides that the result of a blood test, including a HLA test, "shall be admissible in evidence in the trial of the case”. 1982 PA 129. The amendment clearly promulgates a rule of evidence and must be given retroactive effect. This is particularly true since the amendment is remedial in nature, see Lahti v Fosterling, 357 Mich 578; 99 NW2d 490 (1959); Rookledge v Garwood, 340 Mich 444; 65 NW2d 785 (1954), and defendant’s right to have the evidence excluded was not a vested one.

My review of the above cases causes me to conclude that retroactivity means complete retro-*766activity and that a new trial is required if the law of evidence changes while the case is pending at any stage, including post-trial procedures.

The same result was reached by this Court in Tullku, supra. There, the accident which was the subject of the trial occurred on October 4, 1967. The trial took place in October, 1975. In 1978, during the pendency of plaintiffs appeal to the Supreme Court, legislation was enacted affecting the admissibility of evidence in a products liability action. On remand, this Court determined that the statute was to have retroactive effect, noting that the Legislature intended by its enactment to redress grievances and relieve inequities and thus must have "intended the statute to apply to all actions pending, accrued, or future”. Tulkku, supra, p 718. See, also, 73 Am Jur 2d, Statutes, § 354, pp 489-490, and 82 CJS, Statutes, § 424, p 1001.

Here, the statute was amended within the time allowed for the filing of an appeal. As plaintiff did subsequently appeal, this action was pending at the time of the amendment and is therefore governed by the statutes as amended.

In this case, the new act cited above became effective April 20, 1982, just five days after trial and I believe that a new trial is required in order to permit the trial court to weigh the effect of the HLA blood test showing a 91% probability of paternity. Given the closely contested testimony and evidence at trial, the HLA test results may well be of decisive importance to the trial judge in reconsideration. HLA testing is a " 'potentially powerful tool in determining the probability of paternity’ ”. Pizana v Jones, 127 Mich App 123, 128; 339 NW2d 1 (1983), citing Varney v Young, 106 Mich App 545, 547-548; 308 NW2d 276 (1981). *767The exclusion of the test results cannot be considered harmless.

II. Waiver

Prior to trial, plaintiff requested admission into evidence of the HLA test results in her answer to defendant’s motion to quash interrogatories. Although no ruling was made by the trial court on the record, it appears that off-the-record discussions were held regarding the evidence and counsel for plaintiff said at trial that he was not introducing the test. After trial, on May 13, 1982 (i.e., after the effective date of the amendments to MCL 722.716; MSA 25.496), the court signed an order denying the request to have the test results admitted.

This order was obtained by counsel for plaintiff ex parte and he may have done so to protect the record on appeal — although for the reasons stated below, such protection was probably unnecessary.

Defendant claims that by stating to the court that he was not introducing the test, counsel for plaintiff waived his right to raise the issue on appeal. I disagree. At the time of trial, plaintiff was not allowed by law to introduce the HLA blood test results. According to the order of May 13, 1982, she had apparently earlier urged the court to admit the test results, without success. This is supported by plaintiff’s request for admission into evidence of the test results which was included in her answer to defendant’s motion to quash filed on March 3. In any event, counsel’s statement on the record that he was not introducing the test was nothing more than an acknowledgment that he was following the law then in effect. Fairness requires me to hold that an attorney cannot be held to have waived the right to *768introduce evidence by failure to formally do so if, at the time of trial, he or she by statute did not have the right to have the evidence admitted.

In Morris v Radley, 306 Mich 689; 11 NW2d 291 (1943), a defendant did not assert a defense of governmental immunity because the Supreme Court had, in an earlier unrelated case, ruled that that defense was unavailable to a county road commission (one such commission was a defendant in Morris). In a subsequent case, the Supreme Court reversed its earlier opinion.

On áppeal, the Supreme Court set aside the judgment against the defendant road commission, notwithstanding its failure to raise at trial the defense asserted on appeal, because the defendant had understandably relied upon the earlier ruling and the change in the law clearly made a material difference in the likely outcome of the case. Fairness, said the Court, required the setting aside of the earlier judgment.

Applying the same rationale, I find that plaintiffs counsel’s failure to vigorously argue for admission of the test results at trial cannot be held against plaintiff where counsel was restricted in his efforts to introduce the evidence by the then state of the law.

III. Election Between Interrogatories and Testimony

Prior to trial, plaintiff submitted a set of 31 written interrogatories to defendant, which defendant refused to answer, citing Pridemore v Williams, 90 Mich App 483; 282 NW2d 363 (1979). Upon defendant’s refusal to answer the interrogatories, plaintiff moved to prohibit defendant from testifying at trial. The trial court ruled that defen*769dant did not have to answer the interrogatories but could testify at trial if he so chose. Defendant did not take the stand at trial. On appeal, plaintiff argues that the trial court erred in refusing to require defendant to make an election between refusing to answer the interrogatories and testifying at trial. Technically, this issue is moot since defendant subsequently elected not to testify. The situation which would compel an election according to plaintiff therefore never arose. Since I would remand this case for a new trial, however, where the issue would again arise and defendant might wish to testify, I will discuss the matter in order to provide a more complete statement of my view of this case.

In a paternity suit, although competent to do so, "the alleged father shall not be compelled to testify”. MCL 722.715(a); MSA 25.495(a). In Pridemore, supra, this Court determined that this rule also prohibited the service of written interrogatories upon a defendant in a paternity action, pursuant to GCR 1963, 309 and 313.1(2). Where there was a conflict between the Paternity Act, MCL 722.711 et seq.; MSA 25.491 et seq., and the General Court Rules, the provisions of the Paternity Act were held to prevail.

In the instant case, upon defendant’s motion to quash interrogatories, plaintiff asked that defendant be barred from testifying at trial should he elect not to answer the interrogatories. Defendant argued that the holding in Pridemore forbade the serving of interrogatories upon putative fathers and that that holding, together with the statutory provision making defendant’s testimony competent but not subject to compulsion, mandated the conclusion that defendant need not make an election but could testify selectively. The trial judge agreed *770with defendant, quashing the interrogatories and ruling that defendant could testify or not, as he so chose. I, however, disagree with the conclusion reached by the Pridemore Court and find plaintiffs argument more persuasive.

In so doing, I first point out that the Pridemore Court was not faced with the facts or the issue presented in the instant case. The defendant in Pridemore had refused to answer interrogatories which the trial court had then ordered him to answer. The subject of trial testimony was not discussed and the plaintiff did not ask that the defendant be forced to elect between refusing to answer interrogatories and testifying at trial. The issue presented in the instant case, therefore, whether defendant here should have been compelled to make such an election, was not reached by the Pridemore Court. The use of interrogatories in a paternity action, however, an issue resolved in Pridemore, is of underlying importance here. In deciding that defendant could be put to an election, I also would hold that the service of interrogatories upon defendant is not prohibited. The putative father may exercise the statutorily enacted privilege of not answering the interrogatories but nothing in the statute prohibits the mother from submitting interrogatories which defendant may choose to answer.

In Roe v Cherry-Burrell Corp, 28 Mich App 42; 184 NW2d 350 (1970), this Court held, on the authority of GCR 1963, 302.2, that a party claiming a privilege in order to prevent the taking of an expert witness’s deposition could not then offer the testimony of that witness at trial as it pertained to the evidence objected to at the deposition. The Court said:

"The plaintiffs choice is clear; he may either claim *771the privilege or allow the physician to be deposed, and under the court rule he can be put to a choice in advance of trial * * *.” Roe, p 45.

See, also, Eberle v Savon Food Stores, Inc, 30 Mich App 496; 186 NW2d 837 (1971). In Roe, supra, the plaintiffs claim of privilege was based on either the physician-patient or attorney-client privilege or the work product restriction.

The right not to testify asserted here by defendant is also a privilege, since he could testify or not, as he chose. As such, it is governed by GCR 1963, 302.2 because interrogatories must be controlled by the same sanctions which apply to the depositions which were the subject of Roe, the scope of examination and permitted use of the answers being the same for both discovery devices. See 2 Honigman & Hawkins, Michigan Court Rules Annotated (2d ed), p 160. Both statutory and common-law privileges may be invoked. See Wilson v Saginaw Circuit Judge, 370 Mich 404; 122 NW2d 57 (1963), and Eberle, supra. A defendant must therefore elect to either assert his privilege or not; he may not choose to assert it piecemeal. If a defendant elects to assert his privilege, i.e., if upon a retrial he still were to choose not to answer plaintiffs interrogatories, he could not testify at trial regarding the subjects covered by the interrogatories.

In reaching this result, I do not reject the Pride-more Court’s conclusion that, where there is conflict, the provisions of the Paternity Act prevail over the General Court Rules. However, I find no conflict to be evident here. Defendant is not required by the court rules to forego his privilege; he is merely required to assert it consistently. The holding in Pridemore, therefore, goes too far. The service of written interrogatories upon putative fathers is not to be prohibited but should be al*772lowed subject to motions to quash based upon assertion of the statutory privilege. As the Pridemore Court also found, "the use of written interrogatories as a discovery technique in paternity actions is a valid and permissible procedure”. 90 Mich App 490. I agree and see no reason to unnecessarily curtail its use where adequate safeguards exist to protect defendant’s rights and interests. Plaintiff at least should be allowed to attempt discovery. See Eberle, supra, p 500. Should a defendant choose not to testify at trial, however, plaintiff is not entitled to obtain information via discovery which defendant may not otherwise be compelled to divulge. That conclusion is clearly mandated by MCL 722.715(a); MSA 25.495(a). If a defendant chooses to testify, however, he may not surprise or disadvantage a plaintiff by refusing to supply those facts or assertions which he intends to offer at trial and which will obviously, therefore, eventually become known to plaintiff. It is a defendant’s option to testify which is protected by statute, not his desire to offer only selected testimony of a nature and at a time to be determined solely by a defendant. It is worth noting in this regard that, once a defendant testifies, he is subject to cross-examination by the plaintiff. MCL 722.715(a); MSA 25.495(a). I therefore expressly reject the holding reached by a panel of this Court in Pridemore v Williams, supra, and hold that the service of written interrogatories upon a defendant in a paternity action is not prohibited but that such interrogatories may be quashed upon the defendant’s assertion of his privilege not to testify.

If a defendant decides to answer the interrogatories and then decides not to testify, this decision must be honored under MCL 722.715(a); MSA 25.495(a). However, GCR 1963, 309.4, which refers *773to GCR 1963, 302.4, allows interrogatories to be used at trial where the witness is not subject to process or a party is unable to procure the attendance of the witness by a subpoena. Therefore, the interrogatories and the answers could be used by the plaintiff at trial in the same way that a deposition of an unavailable witness can be utilized at trial. A defendant is not prejudiced by the use of interrogatories at trial because he would have answered them voluntarily.

I would reverse the trial court’s order adjudging defendant not to be the father of plaintiffs child and remand for a new trial.