Ronan Farrow—whose unwatchable daytime commentary show was recently axed by MSNBC—is not Frank Sinatra’s son. So says his would-be half-sister Tina Sinatra, who told Roger Friedman the other night that the rumored lineage is impossible. The reason: “Frank had a vasectomy…”

Here’s the passage from Friedman’s piece:

Tina Sinatra laughed when I asked if Mia Farrow’s son Ronan (with Woody Allen) was her brother. Mia let that slip in November 2013 and the rumor caught fire. “Couldn’t be,” Tina told me. “Frank had a vasectomy before that. I don’t know whose son Ronan is.” Mia Farrow had been invited to the dinner but was a no-show. Tina added that Ronan looks “just like Mia’s late brother.”

The very ugly public spat between Woody Allen and the Farrow family over allegations that Allen sexually molested his 7-year-old daughter Dylan Farrow made headlines repeatedly last year, particularly around the time Allen was honored at the 2014 Golden Globe Awards. After the Allen tribute, Ronan Farrow tweeted, “Missed the Woody Allen tribute - did they put the part where a woman publicly confirmed he molested her at age 7 before or after Annie Hall?”

Rumors of Sinatra being Ronan’s father started when Mia admitted in 2013 to having maintained a relationship with him while married to Woody Allen.