Questions & Answers

Ran out of room in my previous comment:

If you date everything not by when you got the positive test but by the ultrasound dating it would make guy #1 more likely to be the father. But really either could be.

You asked if there is "any chance guy #2 could be the father" and the simple answer is yes there is a chance. Really either guy could be the father.

Let's say you ovulated somewhere between 12/20 and 12/23. That would mean the first time you tested on 1/1/17 would have put you testing between 12-15DPO (days past ovulation). You'd most likely have a positive test in this DPO range. Then when you got a positive you'd have been testing between 16-19DPO. Sure you could get a negative on 12DPO and go on to get a positive on 15DPO but a negative on 12DPO followed by a positive is somewhat rare.

If you ovulated between the 26th and the 29th you would have been 6-9DPO when you first tested. It's impossible to get a positive test at only 6DPO and 9DPO is still fairly early so that would make sense. Then when you retested on 1/4/17 you would have been 10-13DPO which is a reasonable time frame for a positive test.

So I'd say based off that guy 2 is more likely to be the father.

More than likely the first one. you can look up your ovulation date. they will have you type in the first day of your last period, and will tell you the exact few day that you could have conceived.

More than likely, it will be the guy #1. Unless you ovulated on the 26th, which is 25 days after your cycle started, it seems very unlikely that he will be the father. It takes at the least, about 9 days after you ovulate to get a positive test. Also, don't worry about not seeing anything on the ultrasound that early. Your levels have to be at least around 2,000 to even see the start of a sac. I went in at 5 weeks 1 day and there was only a sac, no fetal pole yet.