Explain: some doctors say that it's too late in the cycle to conceive 1-2 days before period. others say that you can. which is it?

Too late: It is too late to get pregnant 2 days before your period. In a 28 day cycle, ovulation happens on day 14. The egg survives for a short period of time after that it goes away if not fertilized. Therefore the fertile window is around the time of ovulation. On the other hand sperm can live for 2-3 days, therefore if intercourse happens earlier than the fertile window, pregnancy may sti'll happen.