There’s this:

Man Claiming to Be Bill Clinton’s Son Asks Monica Lewinsky for Former President’s DNA

[…]

“I deserve to know who I am,” he told InsideEdition.com. “I feel in my whole heart he is my father. I am [Hillary Clinton’s] stepson, and Chelsea’s stepbrother. I’m their only son in the world.”

[…]

Star magazine confirmed with a DNA test in 1999 that Williams is not the biological son of Clinton. Williams, however, said he continues to dispute the results since he claims the publication only ran one of the two possible DNA tests available.

First off, there are more that two “possible DNA tests” available.

Secondly, Bill Clinton like many Southerners comes from a long line of Americans with big families. This guy who thinks he’s Bill’s son could take tests like 23andMe or AncestryDNA, each are just $99, and find plenty of cousins. If this guy is indeed Bill’s son, he should show up as not too distant cousins to the many cousins of Bill who are already tested. It would take some research to make sure how he is connected to those people, but it’s done everyday, as we see in those TV shows which reunite adoptees with birth families.