Just bringing up the subject of biological fathers (as opposed to those whose names appear on birth certificates) is repugnant. Leave it to an orange cat to dive in.

Because her mother is a candidate for the presidency, Chelsea Clinton is back in the news, and not just for drawing a $600,000-a-year salary from NBC for doing practically nothing. (That gig ended in 2014.)

Also back, mostly at right-wing news sources that despise the Clintons, is speculation that Bill isn’t her biological father. Truth be told, at age 35 she looks a lot like Webster Hubbell, Hillary’s former law partner who went on to become an associate attorney general.

This story was ratcheted up a level when a new book by Roger Stone and Robert Morrow flatly labeled the speculation as fact. According to WND website, when Mr. Morrow asked Chelsea about it as she signed her children’s book in a bookstore, she replied: “I’m so proud to be my parents’ daughter.”

Give her points for a great choice of words and the grace not to tell a fellow author to piss off.

Chelsea’s campaign appearances will be curtailed this summer as she makes Hillary a grandmother for the second time. (This part we can be sure of.)

Elsewhere in the liberal parallel universe, former MSNBC host Ronan Farrow doesn’t look at all like his legal father, Woody Allen. His mother, Mia Farrow, has admitted that he might “possibly” have been fathered by her ex-husband, Frank Sinatra.

At 28, Mr. Farrow is looking more like his Italian dad every day. Mr. Sinatra is long dead, there has been no DNA testing and none of the other parties seem to care. Good for them.

As Mr. Farrow tweeted in 2013: Listen, we’re all “possibly” Frank Sinatra’s son.