yes it can happen!!1
FYI- textbook knowledge here! once a egg is released (ovulation) it only lives for 24 hours...
I cant see this being realistic.
but its textbook so who knows!
& sperm longest is 7days.
average 3-5
so if may calculated time of conception (sonogram) is may 20th & I had sex on the 24th/25th & it takes up to 36 hrs, is it possible that this may not be the father?
according to wiki it takes approximately 36 hours from the time the man ejaculates for the sperm to fertilize the egg.