If it's actually a menstrual period (and not mid-cycle bleeding), then no, it's not likely to get pregnant on your period. Considering most sperm only live 3 days (though some last up to 5 days) and an egg only lives 12ish hours and an egg is released 12-16 days before your next menstrual cycle, you'd have to have REALLY short cycles for sperm to survive from menstruation until ovulation. If you had sex on day 5 of your period and ovulate on or before day 10 of a 24 day cycle and your uterus is alkaline enough to allow sperm to live a full five days, there's a SLIGHT chance that enough sperm would survive in the fallopian tubes to fertilize the egg....but I wouldn't consider it to be likely to say yes, you can get pregnant during your period. So, in a way, you're both right in my opinion. In an AVERAGE cycle with AVERAGE sperm lasting only 3 days and an AVERAGE ovulation day of CD14, no, you can't get pregnant by having sex during an AVERAGE 5 day menstruation.