It’s been observed in animals so it’s possible it’s true for humans as well, however in genetic ancestry tests, you won’t find that. This concept (referred to as telegony) refers to offspring exhibiting traits that they inherited from the mother’s previous sexual partners who also ejaculated inside of them. If a woman has safe sex, it wouldn’t be possible for telegony to occur. It’s a controversial subject in the scientific world but since animals share 99% of DNA with humans, I don’t see why it’s so far-fetched to say it can’t happen with humans.