Expectant parents Charlie Sheen and Brooke Mueller boosted their chances of conceiving a baby boy by undergoing a fertility procedure dubbed 'sperm spinning,' according to reports.

After fathering three daughters - Sam and Lola with ex-wife Denise Richards and Cassandra with ex-girlfriend Paula Profit - actor Sheen is desperate for a son.

According to the National Enquirer, the pair paid to have the star's X and Y sperm separated, and Mueller was inseminated with just the Y sperm, giving their chances of having a son an 80 per cent boost. And a source close to the couple claims it worked.

Sheen himself hinted that Mueller is carrying a boy, when he announced her pregnancy in August, by saying, "Brooke informed me two days ago that very soon we'd be producing our own version of Two and a Half Men."

But Sheen insists he's not bothered if the baby is a boy or a girl - as long as it's healthy.

In a recent interview, the actor said, "Ultimately, we just want a healthy child. We know everyone says that, but it's the truth."

(This news article provided by World Entertainment News Network)