According to data from the 1991 National Survey of Adolescent Males, condom use is likely to be highest at the beginning of relationships and to decline as the relationship continues. The proportion of sexually active men aged 17-22 who used a condom with their most recent partner declined from 53% the first time they had intercourse with that partner to 44% at the most recent episode. Condom use also decreases with age; 59% of 17-18-year-olds used a condom the first time they had intercourse with their most recent partner, compared with 56% of 19-20-year-olds and 46% of 21-22-year-olds. However, the probability that the female partner used the pill the first time that the couple had sex increased with the man's age--from 21% among 17-18-year-olds to 35% among 21-22-year-olds. Young men were more likely to have used a condom if they thought their partner was sexually inexperienced, and less likely to have done so if they suspected their partner was at high risk for an STD.