Can you get a girl pregnant after only one time?

Yes, it is possible to get a girl pregnant after only one time. Pregnancy can occur if unprotected sex happens during a woman's fertile window. This fertile window is typically around the time of ovulation, which occurs about 14 days before the start of a woman's next period. If sperm is present in a woman's reproductive tract during this time, it can fertilize an egg and result in pregnancy.