Preganancy can result from having intercourse during your fertile window period.
AnnieBrooke gave u the best possible answer and I do agree with her....
Sperm can last five or six days in your system, according to research. That is what gives you a big fertile window -- if you had sex with your hubby on the 10th you could still get pregnant by his sperm when you ovulate on the 14th. Your egg only lasts about 24-36 hours before it is no longer viable. So, yes, you can get pregnant by any sperm in your system on any fertile window day but yes also, you only get pregnant on ovulation day.