Sheen: 'Richards did want my sperm'

Charlie Sheen has stuck by his claims that Denise Richards asked him to donate sperm after their divorce.

Richards - who had two children by Sheen while they were together - denied making the request in an interview on US chatshow Today this week.

A leaked email from Richards to Sheen's new fiancée Brooke Meuller appears to show that she was looking to use the actor's donation to have a child by IVF.

Sheen said: "If any proof can be established that these are not in fact her words and statements verbatim, I openly invite her and would even encourage Ms. Richards to sue me in a court of law."

The pair divorced in August 2006 and have since been fighting a custody battle for their children.