My(23M) gf(24F) told me she is pregnant but I am sterile

I am 23 years old right now and I have sterile syndrome since i am born. I made sure to explain that to my gf(24) and she said she understood.<br><br>We dated for almost a year now, we had sex 3 times a week, I used condoms and she was on the pill so I dont think she is pregnant with our child. We had conversation about abortion and she said she will not do it so if she is actually pregnant she will keep the child.<br><br>Last week we had sex on Monday but she told me she missed her period so she might be pregnant. I told her it is not possible for her to be pregnant but she said she felt something was off, so I suggested her to take an emergency contraceptive pill and go see her doctor. I was at work all day on Friday and she messaged me saying that she went to her doctor and she is actually 5 weeks pregnant. I was shocked when i heard this word from her but i didnt say anything since it would not make sense to tell her that i am the reason for her pregnancy since im sterile.<br><br>She has been acting strange all day, she is not talking much. I think she is starting to believe that I am the father of her child, I want to tell her that it is not possible for me to be the father of her child but i want her opinion on this first.<br><br>How should i tell her i am not the father of her child even tough she is pregnant? What is the best way to explain it to her?