Frank Sinatra underwent a vasectomy so could not have fathered Ronan Farrow, according to his youngest daughter, Tina Sinatra. Showbiz 411's Roger Friedman said that the 66-year-old laughed when he asked her if Mia Farrow's son Ronan was her brother. He said that Tina, who is the daughter of  Sinatra and his first wife Nancy, told him: 'Couldn't be. Frank had a vasectomy before that. I don't know whose son Ronan is.' Scroll down for video . Frank Sinatra (left) underwent a vasectomy so could not have fathered Ronan Farrow, (right) according to his youngest daughter, Tina Sinatra . Mia Farrow had previously admitted the singer may be the father of her Ronan (both pictured) It has never been reported before that Sinatra underwent the medical procedure. In 2013, Mia Farrow admitted that Frank Sinatra may be the father of her son, instead of Woody Allen. Tina Sinatra, 66, ridiculed claims Ronan Farrow was her brother . Rumours . about the parentage of her son Ronan, 27, have long dogged the actress, and she addressed the issue in the interview saying the legendary crooner was 'possibly' his father. Ronan Farrow later responded by tweeting: 'Listen, we're all *possibly* Frank Sinatra's son.' Farrow, now 70, said that Sinatra was the great love of her life, and says, 'We never really split up.' Farrow married Sinatra in 1966 in Las Vegas when she was 21 and he was 50. The marriage fell apart 18 months later when she refused to drop her critically-acclaimed performance in Rosemary's Baby to star in a movie with her husband. They divorced in 1968. Two years later, Farrow married German-Austrian pianist Andre Previn. The couple adopted three children and also had three biological children before divorcing in 1979. In 1980, Farrow started a long-term relationship with Woody Allen, although the two never lived together. She and the children stayed in her massive Upper West Side New York apartment while he had a home on the other side of the city. Farrow became Allen's muse and starred in 13 of his films, most notable Hannah And Her Sisters in 1986. Earlier bonds: Woody Allen and Mia Farrow walk as Mia carries their son Satchel, who later changed his name to Ronan . 1966: Actress Mia Farrow married Sinatra in Las Vegas when she was 21 and he was 50. 1968: The couple split just 18 months after getting married and got divorced. 1971: Mia Farrow then married German-Austrian pianist Andre Previn.They went on to adopt three children - Lark Song, Summer Daisy Song, and Soon-Yi - and had three biological children - twins Matthew and Sascha and finally Fletcher. 1976: Frank Sinatra married Barbara Marx.1979: Farrow and Previn divorced. 1980: Farrow started dating Woody Allen. They adopted two girls - Moses and Dylan. 1987: Farrow gave birth to a boy, Ronan, on December 19. Ronan was the only biological child of the couple. 1992: The couple split when Farrow discovered Allen was having an affair with her oldest adopted daughter Soon-Yi Previn, then 22. 1992 - 1995: Farrow went on to adopt six more children - Tam, Kaeli-Shea, Frankie-Minh, Isaiah Justus, Thaddeus Wilk and Gabriel Wilk. 1998: Frank Sinatra died. He was still with his third wife Barbara Marx at the time of his death after 22 years of marriage. 2013: Farrow has now suggested Sinatra may be Ronan's father as they never 'really split up'. Farrow gave birth to Ronan in 1987 - he was their only biological child. Her relationship with Allen ended in 1992 when she discovered he was having an affair with her oldest adopted daughter, Soon-Yi Previn, then 22. The news that Allen may indeed be his father may not be welcome to Ronan - the pair had a very public falling out when Allen began his romantic relationship with Previn. 'He's my father and married to my sister. That makes me his son and his brother-in-law. That is such a moral transgression,' Ronan has said. 'I cannot see him. I cannot have a relationship with my father and be morally consistent... I lived with all these adopted children, so they are my family. 'To say Soon-Yi was not my sister is an insult to all adopted children,' Ronan said of the relationship. Allen later responded to Farrow's claims saying it was possible that Ronan was not his son. Allen wrote claimed that mother Mia Farrow may have been lying about it for decades. The Annie Hall director said Ronan, his only biological child with Farrow, ‘looks a lot like Frank’ thanks to his blue eyes and similar facial features. Allen said that if it were true then Farrow would have kept a dark secret during their bitter custody battle 21 years ago to make him pay child support. In a 2005 interview, Allen confirmed that he no longer has relationships with his three children from his relationship with Farrow. 'Well, I feel terrible about it. I spent millions of dollars and fought in court for years to do it, but could not swing it,' he told Vanity Fair. When Vanity Fair asked Sinatra's daughter about Ronan being treated as if he were a member of her family, Nancy Sinatra Jr told them: 'He is a big part of us, and we are blessed to have him in our lives.'
Tina Sinatra, 66, laughed when he asked if Mia Farrow's son Ronan, 27,  was her brother .
She said: 'Couldn't be. Frank had a vasectomy before that. I don't know whose son Ronan is'
In 2013, Mia Farrow admitted that Frank Sinatra may be the father of her son, instead of Woody Allen .