Jolene Kelleher
Jolene Kelleher answered
I had sex on dec 9th and 29th, my due date is sep 19th...although, I don't know when my last period was. I never kept track of them..can anyone tell me which day I most likely got pregnant so I can have a better idea of who the father is?

Sperm lasts up to 7 days inside you so if you had sex before the date or inbetween then you have another potential father.  

Ask your doctor or midwife and they should be able to tell you and after this baby think of some birth control and a period tracker.