Hey guys, just a quick (probably very silly) question thats been on my mind as of late. I've already asked this to a couple of people, but neither were 100% positive with their answer so I thought I might try somewhere else.

Ok well here's the story. My friend has been having unprotected sex with another guy (not me) for a few months now, and having him pull out before ejaculation everytime (yes, im aware pregnancy is still very much possible). While she was 6-7 days late with her period, her and I engaged in unprotected sex (I pulled out well, well before ejaculation), and I just found out she's gone a further 1.5 weeks of being overdue, which brings her up to 2.5 weeks total. I assume this is a decent sign that she may be pregnant.

My question is: since she was already late when we had intercourse, what are the chances, if any, that she may be pregnant off me and not the other male.

Thanks for your time and help!