One of the things I love about Dimajio's work is that it's very realistic. The chances of a woman getting pregnant from unprotected sex are actually lower than you think, which is why there are so many videos online of friends and family congratulating her on her pregnancy.I was more talking about how the logic is inversed in Pineapple Express: Julia can only get pregnant if you are a cuck/sharing her with your best friend - and hide the condoms that one time. But, if Julia is cheating on you, she gets creampied several times on her own volition and... nothing happens. You would expect one of the endings to be that Julia leaves you for Cornell once she finds out she is pregnant with his kid.
And in many of his works, the female protagonist has unprotected sex and the couple just ‘what possibly go wrong’ and move on. Even IRL and in general, unprotected sex is a boundary issue, not a pregnancy issue.
Given the number of times Julia has had sex, I think it's very unlikely that she could have had Cornell's child in any case.
There is one other instance in the game where Julia gets pregnant, and it's a no corruption vanilla pass, which means she's 100% pregnant with the MC's child.
IRL, whether MC hid the condom or not, it's most likely the MC's child in either case.
You can also choose to have the MC tell Julia that he can't stand her cheating, which would end the game. I think this is probably closer to the ending where Julia ends up with Cornell.