I had sex with a guy december 10th . i also had sex with another guy december 12th & december 20th . my conception date based off my first ultrasound at 6 weeks and 1 day is december 18th . who is more likely to be the father ?

The only worthwhile answer & one that will hold up in court proceedings will be a DNA based paternity test. The NIPP is a non-invasive test performed on your blood as early as 8 weeks. They find fetal DNA in your blood & can test it for a variety of things including paternity. Ultrasounds and projected dates can give data, but a surprise at delivery is not worth a wrong call.