Is an ultra sound 100% accurate with conception date I

Patient: Is an ultra sound 100% accurate with conception date. I calculated that I ovulated on the 4th but I slept with two guys. One on the 4th and one on the 7t . Is it possible to get pregnant 3 days after ovulation or if my calculation was wrong could I be pregnant with the second guy or first more likely?

Doctor: Hello,Thanks for the query.Ovulation occurs on 14th day of the menstrual cycle. However, it can occur anytime betw een 10th to 18th day of the cycle, considering the interval to be the fertile period of the menstrual cycle. In your case the dates of sexual intercourse are very close to one another, that is 4th and 7th. An ultrasound is not 100 percent accurate in predicting the conception date, however, it is 99% reliable. It is not possible to predict which sexual act lead to the pregnancy as the interval between two intercourse dates in very close and both lie in the ovulation time. A genetic testing and DNA karyotyping can tell you who the father is for the child.Hope this helped.Regards