Hi I was wondering how long does it take conceive.Also my doctor says my conception date is June 15, could I have gottan pregnant if I had sex on June 14th.

Calculating conception dates is an inexact science and can be off 2 weeks either way. So yes the sex on June 14 could have resulted in conception. It can take several days for fertilization.

If there is a question of paternity, the only way to tell for sure is with a DNA test after birth.