Ending a bloodline is a bit much. The sperm factory doesn't shut down forevermore just because a guy got lied to. Men can have children into their 70s or later. The ildest dather in record was 94 when he sired his first child. He had two more after that.

Unless he's had a vasectomy when he found out his kid isn't his, he can have more children.

And that's not even discussing the percentage odnmen out there who have children they don't know about because of sexual recklessness. Not to deflect, but the reality is that since men don't carry children, they never really know (outside abstinence) whether they have fathered a child or not unless the mother tells them or asks for support. It's not like men have a behavioral impetus to follow up on all their sexual partners to make sure they're not missing out on fatherhood.