[1] Defendant preserves and presents ten assignments of error. He first contends the court erred in overruling his objection to certain testimony regarding crimes allegedly committed by him prior to the alleged commission of the crimes for which he was on trial. In spite of his objection, the State was allowed to introduce testimony that the defendant had committed the crimes of rape, burglary, and crime against nature on the night of 31 January 1976, one week before the alleged commission of the crimes in the instant case.
It is well settled in this State that if a criminal defendant has not testified, evidence that he has committed another distinct, independent, separate offense is not admissible if its only relevancy is to show the character of the defendant or his disposition to commit an offense of the nature of the one for which he is presently on trial. State v. Felton, 283 N.C. 368, 196 S.E. 2d 239 (1973); State v. McClain, 240 N.C. 171, 81 S.E. 2d 364 (1954). If, however, the evidence in question tends to prove any fact relevant to the charge on which the defendant is presently on trial, it is not inadmissible merely because it also shows him *685to have been guilty of another, independent crime. State v. Felton, supra; State v. McClain, supra.
The decisions in this jurisdiction have been
. . markedly liberal in holding evidence of similar sex offenses admissible ... [to show knowledge, intent, motive, plan or design, identity, etc.] especially when the sex impulse manifested is of an unusual or ‘unnatural’ character.” 1 Stansbury, N. C. Evidence, § 92 (Brandis rev. 1973). See also State v. Spain, 3 N.C. App. 266, 164 S.E. 2d 486 (1968).
Our courts have repeatedly held other or repeated sex acts to be admissible to show: lack of consent, State v. Parish, 104 N.C. 679, 10 S.E. 457 (1889); the “unnatural” lust of the defendant, State v. Edwards, 224 N.C. 527, 31 S.E. 2d 516 (1944); the defendant’s attitude, animus, and purpose, State v. Davis, 229 N.C. 386, 50 S.E. 2d 37 (1948); intent, design or guilt on the grounds of being in corroboration, State v. Browder, 252 N.C. 35, 112 S.E. 2d 728 (1960); modus operandi or common plan and identity of defendant, State v. McClain, 282 N.C. 357, 193 S.E. 2d 108 (1972); and quo animo or state of mind, State v. Humphrey, 283 N.C. 570, 196 S.E. 2d 516 (1973).
The evidence here in question was clearly relevant to show lack of consent, defendant’s unnatural lust, identity as the perpetrator, and defendant’s intent or state of mind. The evidence was therefore admissible.
[2] Defendant next contends the court erred in denying his motion to strike Patricia Gainey’s testimony relating to the fact that defendant had previously been in prison. On cross-examination the defendant elicited the following testimony from Patricia Gainey: “I do have a telephone in my apartment, but I did not call the police after he left.” Defendant’s counsel then asked: “Other than asking him to stop, you didn’t resist him on this occasion, did you?” The response was: “No, sir. When I came back, I didn’t call the Police because he had just gotten home from prison. He was on his way to Florida for trial.” The defendant moved to strike this answer as unresponsive but the court denied the motion by asserting that defendant had “opened the door.” Immediately after the court’s ruling, Mrs. Gainey continued her testimony: “He just came home the day before. He was on bond from Florida. I wanted to give him a chance to *686be with his daughter. She loves him. I didn’t want to see him back in jail, and he still had Sarah Jean too.”
We hold that there was no abuse of discretion on the part of the trial judge in refusing to strike what appeared to be a full answer to defendant’s question concerning her failure to call the police. Moreover, the prosecuting witness subsequently testified, without objection or a motion to strike, that defendant had just gotten out of prison and was going to Florida in a week “for armed robbery.” Consequently, defendant’s original objection to the evidence was lost since evidence of like import was admitted after the admission of the challenged testimony. State v. Jarrett, 271 N.C. 576, 157 S.E. 2d 4 (1967). This assignment of error is therefore overruled.
[3] Defendant’s fourth assignment of error relates to the admission over objection of a physician’s testimony concerning a microscopic examination of a slide and the results thereof. He contends the testimony about the examination of the vaginal fluid of the prosecuting witness failed to identify the sperma-tozoons which were found as being “human spermatozoon.” This contention is untenable. Nowhere is there even a scintilla of evidence that the sperm could have been other than human. The State does not have the burden of offering scientific evidence to prove that the specific sperm found came from a specific individual. Prosecutrix testified to the completed act of intercourse. There is no question of mistaken identity. The challenged evidence tended to show penetration, one of the essential elements of rape, and was corroborative of prosecuting witness. It was properly admitted. See State v. McNeil, 277 N.C. 162, 176 S.E. 2d 732 (1970).
[4] Defendant contends, in his fifth assignment of error, that the court erred in allowing the pathologist to testify regarding his analysis of a slide because the State failed to establish a complete chain of custody of the slide from the time it was prepared until the time it was analyzed by the pathologist. State’s testimony tended to show, however, that when the slide was prepared the prosecuting witness’s name was placed on it; that the slide was then placed in a “rape box”; that the box was then locked; that the box always remains in the emergency room until the pathology department comes to get it; and that the pathology department did in fact receive the slide two days later for pathological examination. We find that this evidence estab*687lishes a chain of custody sufficient to support allowance of the challenged testimony. See State v. Preston, 9 N.C. App. 71, 175 S.E. 2d 705 (1970). In any event, there was additional evidence of penetration from the prosecuting witness who testified in much detail on cross-examination concerning the sexual assault upon her by the defendant on 6 February 1976. She testified: “He got on the bed and had intercourse with me. . . . After we had intercourse I went to the bathroom to clean up.” It necessarily follows that her use of the phrase “sexual intercourse” encompasses actual penetration. State v. Vinson, 287 N.C. 326, 215 S.E. 2d 60 (1975). We therefore conclude that there was substantial evidence of penetration even without the expert testimony concerning the analysis of the slide. Hence, any possible error in admitting the slide testimony was harmless.
[5] In defendant’s sixth assignment of error he contends the court erred in admitting into evidence a fingerprint card taken when the defendant was arrested on a prior occasion in 1966, because it tends to show that he committed an earlier offense. The card admitted into evidence did not, however, list a single arrest, indictment, or conviction and the only data visible on the card was a right index fingerprint. Moreover, the only evidence admitted before the jury relating the admission of the fingerprint identification card to any eárlier criminal offenses was the statement of Captain Turner that he had had occasion to take fingerprints of individuals and place them on fingerprint cards; that he had seen the fingerprint card in question at the identification bureau of the Wilmington Police Department; that he made defendant’s fingerprint impressions from defendant’s right hand index finger; and that he could identify State’s exhibit of the card as being the same card as the one he used in 1966. No inference arising from this testimony could prejudice the jury in their consideration of defendant’s guilt. See State v. Jackson, 284 N.C. 321, 200 S.E. 2d 626 (1973). This assignment of error is without merit.
[6] In defendant’s seventh assignment of error he contends the court erred in sustaining the objection of the State to the following question on re-cross examination: “It is true that you have had intercourse with Clifton Justice, is it not?” If allowed to answer, she would have said “Yes, Sir.” Defendant contends the question was relevant to explain the presence of sperm after the alleged rape. Just prior to this question the defense had *688elicited from the prosecuting witness testimony to the effect that she had not had intercourse with Clifton Justice during the period of time in which the alleged assault by the defendant had occurred, which was between 31 January 1976 and the night of 6 February 1976. Thus, since the prosecuting witness had denied having intercourse with Clifton Justice immediately prior to the time of the alleged crime, the defendant’s contention that the question was relevant is without merit.
Defendant’s remaining assignments of error are without merit and are overruled.
No error.
Judges Morris and Vaughn concur.