Paternity Uncertainty: Understanding Pregnancy Timeline & Probability

Question
A girl I was seeing for while, told me now that she is pregnant. My question is she started her last period on Nov 2 and ended on Nov 9. We had sexual intercourse on Nov 10 and Nov 15. But then she had intercourse with somebody else on the weekend of the 22nd through the 26th.  Who is more likely the father me or the other person. Thank You

Answer
Dear John,

A woman can get pregnant at any time during her cycle. However, there is a time that she is more fertile, which is sometimes called her "fertile window". This is typically the 11th-21st days of her cycle (Day 1 being the 1st day of her period).

With the information you've given me, if she has typical 28-29 day cycles, her fertile window would have been 11/12-11/22. And she most likely would have ovulated around 11/15. Because an egg only lives about 24 hours after being released unless fertilized, the odds are better that conception would have taken place then, rather than later.

I hope this helps and answers your question. I wish you a happy Christmas season.

Brenda