Paternity Uncertainty: Identifying the Father of Your Baby

Question
I am confused and was wondering if you could help. last day of LMP was dec. 13 2006. I had sex with my husband on dec. 21 and than had sex with another man on dec. 31. My due date is sept.19 with a girl. I am confused who the father could be. I have had a previous mis carriage before from my husband could that make a difference that maybe his sperm doesn't work with my egg? I have also heard another mans sperm can kill anothers is that true? Also I was having frequent sex with the other man all through out the beginning of dec and begginnig of jan as well. I am confused and really need to know.

Answer
Dear Amy,

If your LMP was 12/13/06, I calculate (based on 28 day cycles) that your estimated ovulation/conception date would have been about 12/27 or 12/28 and your due date would be 9/20. Now, sperm cells can survive once past the cervix for up to five days under ideal conditions.  And an egg will only survive for up to 24 hours once released at ovulation. So this presents a quandary with the dates that you gave me.

If I had to GUESS, I'd say probably the 12/21 encounter, but if you happened to ovulate late in the cycle or have cycles longer than 28 days, it could be the 12/31 encounter. You just may not know until testing is done. As far as killing of sperm - no, they all just swim around waiting for that egg.

I wish you well!

Brenda