I mean yeah he didn’t check but he thinks that he’s not his daughter cause he knows his past ex wife cheated on him a lot.
but wasn't it like he saw that her blood type wasn't the same as him or couldn't cme from him ?
I understood it like that ...
Actually, there is some validity to determining paternity through blood type.
https://www.nature.com/scitable/topicpage/paternity-testing-blood-types-and-dna-374/#:~:text=In%20cases%20of%20questioned%20paternity,to%20all%20of%20his%20offspring.
"In cases of questioned paternity, ABO blood-typing can be used to exclude a man from being a child's father. For example, a man who has type AB blood could not father a child with type O blood, because he would pass on either the A or the B allele to all of his offspring."
You can't find out if the child isn't your's by blood test. lol. This is even dumber than saying vasectomies aren't reliable when they have a less than 1% chance of failure.