Neither of the notorious Kray twins fathered any children during their lifetime, and only one of them was ever married before the gangster twins' long prison stays. While it is certainly possible that either or both of them may have fathered children illegitimately, none are known, nor have there even really been any notable rumours of such.
Reggie Kray, the only twin who ever married outside of prison, married Frances Shea in 1965. Two years later, while separated from Reggie and reportedly in the process of trying to get an annulment, Frances died. Her death was ruled a suicide, but there were later rumours that Frances may have actually been killed by Reg's twin brother Ron.
Reggie married again in 1997, marrying Roberta Jones while he was still in prison, with whom he spent the final weeks of his life, having been released from prison in 2000 on compassionate grounds due to inoperable bladder cancer. Reggie died on 1 October 2000.
Ronnie Kray was declared insane when convicted and committed to Broadmoor Hospital, where he remained until his death. Ron married twice while imprisoned, first marrying Elaine Mildener in 1985, whom he divorced in 1989 and marrying Kate Howard that same year. They divorced in 1994, and Ronnie died the following year in Broadmoor on 17 March 1995 of a heart attack.
On a somewhat ironic note, Ronnie Kray had almost died in 1942 from a head injury resulting from a fight with his twin brother. Reggie and Ronnie both eventually became somewhat successful amateur boxers before their gangster activities took precedence.
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