I am currently 31 weeks pregnant I have a due date of May 4, I need to know who the father of my baby is. I had sex w/ a coworker July 28 but he never came in me then I had sex w my boyfriend July 27, 29 and so on. September I found out I was pregnant and my due date is May 4 according to my ultrasound, and my Lmp was July 19.

As dates are NOT an exact science, the ONLY way to find out who the father is would be a DNA test AFTER the birth..

Estimated delivery and conception dates are estimates, So give or take two weeks you can get a idea of when conception happened. There is no way till after the baby is born and you do a DNA test will you know for sure.

The only way to know for sure is a dna a test.