I'm 6 weeks and 3 days according to my last period I had unprotected sex July 5th with a man that's not my husband. I had an ultrasound and it says the baby is 5 weeks. I know sperm can live for 3 to 5 days... so should I wait to see if the conception date changes?

THe extra info doesn't matter... the fact is estimated fetus ages are rough guesses... very rough guesses, they are only accurate to plus or minus 2 weeks. That means anyone you slept with that entire month might be the father.


DNA testing after the child's birth is the ONLY way to know if you slept with more than one person during that time frame.

Sorry, does not work that exact. Conception dates are estimates based on average fetus size. They can be off at least give or take a week. And even off two weeks.

If you had sex with two different people within a week of each other there will be no way to know the father till the child is born and you do a DNA test