INTRODUCTION:Freud opined that condom use during penile-vaginal intercourse (PVI), like sexual activities other than PVI, led to a detrimental effect on orgasm that fueled the neuroses. Although this hypothesis had not been empirically tested, Freud's hypothesis that inability to have a (PVI) vaginal orgasm is a sign of psychological immaturity has recently received empirical support. AIMS:The objective is to examine the hypotheses that use of immature psychological defense mechanisms correlates directly with frequency of condom use during PVI, but inversely with frequency of PVI without condoms. An additional aim is to examine the independent contributions of frequency of PVI with and without condoms, and different triggers of orgasm, in predicting the use of immature defense mechanisms. METHODS:Two hundred ten Portuguese participants (99 women) reported their frequency of PVI with and without condoms, and frequency of orgasms from different sexual activities during the preceding month, and also completed the Defense Style Questionnaire (DSQ-40). MAIN OUTCOME MEASURE:The association of DSQ-40 immature defenses (correlated with indices of psychopathology) with past month frequency of PVI with and without condoms, and orgasms from different sexual behaviors. RESULTS:Frequency of PVI with condoms correlated directly with use of immature defenses. Frequency of PVI without condoms correlated inversely with use of immature and neurotic defenses. Results were not confounded by relationship status, age, cohabitation, or social desirability responding. Regression analyses revealed that immature defenses were independently predicted by condom use for PVI and by masturbation orgasms (for both sexes). For women additional predictors were lack of vaginal orgasm, and orgasm from clitoral masturbation during PVI. CONCLUSIONS:The results are consistent with condom use during PVI being associated with psychological immaturity and predisposition to poorer mental health.