a dna paternity test is the only positive way to identify the father of a baby. the fact you did not ejaculate inside the woman does not mean you did not deposit semen inside her. pre-ejaculate fluid can contain sperm which can fertilize an egg. if you used a condom the chances are low that you are the father of course. ultrasounds are quite accurate in determining the age of the baby but they cannot tell the exact date a woman conceived especially if you're talking about multiple potential fertilizations that occurred just seven days (or less) apart. i'm sorry you're dealing with this. it seems the only way to answer the question of whether or not you've fathered this child is to take a dna test. best wishes to you.
girl i had sex supposidly had sex with me and one other a week apart how accurate & sure is it to find out who . im not sure shes telling the truth about it just being just 2 guys. how accurate are ultrasounds can they tell the exact day that you concieved. i had sex with her on saturday july 21 and she supposidly started her period thursday july 26 and i did not cum in her so what are the chances that it is mine? . and she said the only other person that she slept with was on july 28. and during the first 3 months can they tell exactly down to the day how far along you are?