Richard Lee Helzer was

charged in Alpena County with committing two acts of gross indecency with another male, contrary to MCL 750.338; MSA 28.570.1 In the same two-count information, he was further charged with being a sexually delinquent person at the time of the offenses. See, also, MCL 750.338; MSA 28.570.2 Conviction of gross indecency carries a maximum penalty of five years imprisonment.3 However, the additional penalty provided upon a finding of sexual delinquency allows an alternate confinement of one day to life imprisonment.4

Defendant Helzer was convicted by jury on the principal two charges of gross indecency.5 Subsequently, he was separately convicted by the same jury of being a sexually delinquent person at the *415time the acts occurred.6 As a result of the convictions, he was sentenced concurrently to from ten years to life on each count.

Defendant appealed to the Court of Appeals, alleging that, as regards the bifurcated gross indecency and sexually delinquent person charges, he was charged with but a single statutory offense carrying a possible life sentence and therefore was entitled to 20 peremptory jury challenges. At trial, he had been allowed only the five challenges required by the possible penalty available for a gross indecency prosecution. The Court of Appeals reversed7 on the basis of this claim, ordering a new trial as to all charges. We granted leave to appeal. 399 Mich 824 (1977).

The question we will address on this appeal is whether in a gross indecency prosecution, where defendant is also charged with sexual delinquency, reversible error occurs when the court refuses defendant’s request for 20 peremptory jury challenges, even though the separate charge of sexual delinquency carries a possible penalty of life imprisonment. We reverse the Court of Appeals order for a totally new trial. We find defendant’s trial on the principal charges of gross indecency without error. However, we do find error in the trial court’s denial of defendant’s request for 20 peremptory jury challenges incident to his prosecu*416tion as a sexually delinquent person and so remand for hearing before a jury separately empaneled to decide this question.

I

Defendant was convicted of two offenses involving gross indecency. The statute relating to gross indecency defines the offense in the following way:

"Any male person who, in public or in private, commits or is a party to the commission of or procures or attempts to procure the commission by any male person of any act of gross indecency with another male person shall be guilty of a felony, punishable by imprisonment in the state prison for not more than 5 years, or by a fine of not more than $2,500.00.” MCL 750.338; MSA 28.570.

Additionally, the statute provides that defendant may be declared a sexually delinquent person at the time the offense8 occurred:

"[I]f such person was at the time of the said offense a sexually delinquent person, [then he] may be [punished] by imprisonment in the state prison for an indeterminate term, the minimum of which shall be 1 day and the maximum of which shall be life.” MCL 750.338; MSA 28.570.

Similar sexual delinquency provisions exist in several other criminal statutes. See MCL 750.158; MSA 28.355 (sodomy); MCL 750.335a; MSA 28.567(1) (indecent exposure); MCL 750.338a; MSA *41728.570(1) (gross indecency, females); MCL 750.338b; MSA 28.570(2) (gross indecency, male-female).

In order to convict defendant as a sexual delinquent, evidence9 of delinquency, as defined by MCL 750.10a; MSA 28.200(1), must be established beyond a reasonable doubt:

"The term 'sexually delinquent person’ when used in this act shall mean any person whose sexual behavior is characterized by repetitive or compulsive acts which indicate a disregard of consequences or the recognized rights of others, or by the use of force upon another person in attempting sex relations of either a heterosexual or homosexual nature, or by the commission of sexual aggressions against children under the age of 16.”

Conviction of sexual delinquency can be obtained only in conjunction with conviction on the principal charge.10 Yet, sexual delinquency is a matter of sentencing, unrelated to proof of the principal charge. No additional element of "sexual delinquency” need be proven in order to convict on the principal charge.

Accordingly, what activates the sexual delinquency provision is proof of guilt of a principal criminal offense. However, coupled with this fact, the sexual delinquency hearing itself must prove that defendant has committed "repetitive or compulsive acts which indicate a disregard of conse*418quences or the recognized rights of others”, or acts of force used "upon another person in attempting sex relations of either a heterosexual or homosexual nature”, or acts of sexual aggression committed "against children under the age of 16.” MCL 750.10a; MSA 28.200(1). (Emphasis added.)

It is also clear that proof of the sexual delinquency charge may involve more than simple ministerial considerations.11 Very broad substantive factors come into play when the court or jury decide this question. MCL 767.61a; MSA 28.1001(1)12 provides for a separate hearing and *419record,13 involving psychiatric and expert testimony on the question.14 Even where defendant pleads guilty, the court is ordered to separately investigate the charge of sexual delinquency.15 Language in this statute specifically characterizes sexual delinquency as "an alternate sentence to imprisonment”. See MCL 767.61a; MSA 28.1001(1). (Emphasis added.) In short, this particular provision reflects legislative intent to construe sexual delinquency as a separate, alternate form of sentencing.

Consequently, we are led to an interpretation different than that adopted by the Court of Appeals. That Court’s opinion found sexual delinquency to be entirely self-contained in MCL 750.338; MSA 28.570, and thus simply a penalty enhancement provision related to the principal gross indecency charge.16 To the contrary, we find sexual delinquency to be an alternate sentencing provision tied to a larger statutory scheme. Further, we find the nature of the sexual delinquency hearing itself inconsistent with a simple penalty enhancement rationale. We also find the role of the fact finder highly discretionary in deciding the *420delinquency question. Finally, Vre note the risk of extreme punishment involved with a finding of sexual delinquency. All of these considerations require us to reject the approach taken by the Court of Appeals.

II

A close examination of the legislative history of sexual delinquency demonstrates a sound basis for an alternate sentencing interpretation. At the time the concept became part of Michigan law, related statutory provisions were enacted17 which clearly indicate sexual delinquency was conceived as possible mental illness precluding a fixed sentence. The concept of sexual delinquency was included in the then-existing mental health code18 and Department of Corrections Act,19 which specifically provided for treatment and early release upon satisfactory review by the parole board. The intended result entailed a more flexible and less determinate sentencing framework than set terms of imprisonment. This flexible form of incarceration was meant to entirely replace the more structured and limited sentence provided upon conviction of the principal charge.

Further, this alternate context for handling sexually delinquent persons was explicitly tied to other criminal provisions20 and, by analogy, even *421to legislation dealing with civil commitment.21 In sum, sexual delinquency was part of a much broader scheme of rehabilitation involving a sentence adjusted to defendant’s treatment and recovery from possible mental illness. Thus the sentence for being sexually delinquent was not primarily penal. Punishment within a specific limited period for the principal offense was reserved for those whose psychiatric histories, considered after conviction on the principal charge, reflected no serious tendency toward pathologically repetitive, compulsive, forceful or aggressive acts. So conceived, the sexually delinquent person concept was clearly intended to entail a more flexible, alternate form of sentencing.

Since the legislation was originally enacted, numerous changes have occurred not only in statutes which specifically included the sexual delinquency concept, but also in legislation related to other forms of sexual conduct considered criminal. The wording in the then-existing mental health code, including sexual delinquency in the definition of mental illness, was deleted.22 Further, the Mental Health Code was completely revised four years ago.23 Authority now exists for a finding of "guilty but mentally ill” in criminal prosecutions, which might parallel the sexual delinquency concept as included in the old mental health code.24 Provision *422for treatment and early release of sexual delinquents, which was included in the Department of Corrections Act, was amended out of that statute.25 Similarly, references to sexual delinquency originally found in other legislation have been deleted as new or revised law has appeared.26 In short, sexual delinquency is now limited to five specific criminal provisions, three of which arise from the same criminal conduct.27 Thus constituted, sexual delinquency is a seldom-used category of alternate sentencing, now less explicitly rehabilitative. Provision for treatment is now confined to the normal facilities available to all prison inmates.28

Ill

We conclude that in order to fairly proceed against a defendant under this modified statutory scheme, the alternate nature of the sentence requires a hearing and record before a separate jury in cases where defendant does not waive jury trial. The substantial function and discretion of the jury *423in hearing the sexual delinquency charge,29 the high potential for automatic conviction were the original jury to hear the delinquency charge and the penalty of life imprisonment possible upon finding sexual delinquency all inform our order for separate jury consideration.30 Within the special context of the sexual delinquency hearing, we find that these circumstances distinguish this proceeding from any analogy to habitual offender proceedings. See People v Stratton, 13 Mich App 350; 164 NW2d 555 (1968).

The trial court cannot predict at the outset whether a defendant will actually be prejudiced by having the same jury decide both the principal charge and the sexual delinquency charge. However, the potential for prejudice is inescapable, given the broad function and wide discretion necessarily accorded the jury in the sexual delinquency hearing. Much more is involved than simply determining whether this defendant is the person convicted of specific prior offenses.31 Indeed, acts not necessarily resulting in criminal convictions may be considered under the statute. See MCL 750.10a; MSA 28.200(1). Furthermore, the definition of a sexually delinquent person allows, and in fact must depend upon, consideration of the prior principal sexual offense. Consequently, we find the possibility too real that a jury which only shortly before had found defendant guilty beyond a reasonable doubt on the principal sexual offense might without responsible deliberation conclude he was also a sexually delinquent person. In short, *424the likelihood of an automatic conviction in this subsequent proceeding requires us to order a separate jury.

Additionally, in view of the potential life sentence under the sexual delinquency charge, if the same jury hears both charges a defendant is entitled to 20 peremptory challenges in the empaneling the original jury. However, if the need for a second jury is left to the discretion of the trial court and the court finds a different jury necessary to avoid prejudice in trying the sexual delinquency charge, then the time and expense in proceeding with 20 peremptory challenges at the beginning of the trial is wasted. We find this situation incongruous.

As a result, we conclude that the decision to empanel a separate jury should not be left to the discretion of the trial judge. Unless waived by the defendant, we shall require that a second jury be provided in every case to decide the sexual delinquency charge. The second jury should be empaneled before the same trial judge immediately after conviction on the principal charge.

Further, because defendant is separately tried on the charge of sexual delinquency, which carries a possible sentence of life in prison, he is entitled to 20 peremptory challenges in the empaneling of this jury. On the other hand, at the time the initial jury is empaneled on the principal charge, defendant should be allowed only the number of peremptory challenges appropriate to the possible sentence on that charge.

Moreover, though defendant is separately tried by two different juries, the charge against him for sexual delinquency must be brought before trial on the principal charge begins. The statute mandates that result by including the word "shall” in the *425relevant language of MCL 767.61a; MSA 28.1001(1):

"In any prosecution for an offense committed by a sexually delinquent person for which may be imposed an alternate sentence to imprisonment for an indeterminate term, the minimum of which is 1 day and the maximum of which is life, the indictment shall charge the offense and may also charge that the defendant was, at the time said offense was committed, a sexually delinquent person.” (Emphasis added.)

Thus, if brought at all, a charge of sexual delinquency must be included in the original indictment. The word "may” in the statute refers to the option available to the prosecutor, indicating the sexual delinquency charge may or may not be included. This language does not allow a subsequent information to be filed after the principal charge is tried.

We would contrast this provision with the habitual offender statute.32 In the case of sexual delinquency, ascertaining whether a prosecutor knew or should have known of circumstances which would lead him to add sexual delinquency to the information would be more difficult to establish with certainty. Consequently, determining the prosecutor’s good faith discovery of prior convictions in habitual offender cases is not reasoning which can be transposed to the sexual delinquency context.

After the trial begins, the prosecutor will have waived the opportunity to bring a sexual delinquency charge. By imposing this time limit, we avoid late charges which would prejudice defend*426ant. The substantive character of the sexual delinquency hearing and the extreme penalty possible weigh in our decision. Ideally, the original indictment should include both principal charges and the charge of sexual delinquency. However, we find no impropriety in allowing amendments of the indictment or information prior to trial. Thus, if the prosecutor decides during the period of trial preparation that a charge of sexual delinquency is appropriate, he should be permitted to modify the information. Beyond this point, he waives any right to bring such prosecution.

Furthermore, we hold that no reference to the sexual delinquency charge should be made to the jury trying the principal charge.33 Given the provision for separate juries, absolutely no need remains to acquaint the jury hearing the principal charge with the possible subsequent conviction of defendant as a sexually delinquent person. Discovery during trial of the principal charge that the jury hearing that case has learned of the sexual delinquency charge will henceforth be grounds for mistrial on the principal charge or reversible error on appeal. The two charges must be tried separately. Basic fairness to defendant requires this holding.

IV

Considering defendant’s position in the present case, we find that the trial held on the principal charge was procedurally acceptable. He was charged in the original two-count information with both the principal crime of gross indecency and sexual delinquency. Defendant was provided with *427only five peremptory challenges during voir dire on the principal charge. The charge of sexual delinquency was not placed before the jury during trial or deliberations on the principal charge. Only after the verdict of guilty on the principal charge did the court acquaint the jury with the charge of sexual delinquency. We thus find no error in the proceeding to this point and so affirm defendant’s conviction of the principal offenses of gross indecency.

What we find objectionable is the trial court’s decision to allow the same jury hearing the principal charge to decide the subsequent matter of sexual delinquency and, further, to deny defendant the right to 20 peremptory jury challenges on that charge. We thus affirm the Court of Appeals on this basic point; but reverse their order for an entirely new trial. We remand only for hearing before a separately empaneled jury should the prosecutor decide to pursue the sexual delinquency charge. Defendant should be accorded the full 20 peremptory challenges appropriate to the possible life sentence. Should the prosecutor choose not to proceed upon the sexual delinquency charge, or should the defendant be found not guilty, defendant will be resentenced by the trial court only on the principal charge.

Given our ruling of procedural error in the sexual delinquency proceeding, we will not now consider the larger constitutional claim first alleged by defendant in his cross-appeal to this Court. Should defendant be found sexually delinquent on proper hearing below, then appeal on constitutional grounds may be brought and fairly considered in the correct order.

Affirmed in part; reversed in part and remanded to the trial court for further proceedings.

(dissenting). For the reasons set forth in my opinion in People v Winford, ante, 404 Mich 409; 273 NW2d 58 (1978), I am convinced the sexual delinquency statute is unconstitutional. Accordingly I see no reason for considering the procedural questions treated here.