Hugh Hefner is trying for a baby with girlfriend Holly Madison.

The 28-year-old blonde and 81-year-old Playboy founder are so desperate for a baby they are spending nearly all their time having sex.

She said: "We do want a baby. There has been lots of trying - lots of trying!"My perfect Valentine's Day (14.02.08) present would be a house and a kid."Although he is trying for a baby, Hugh refuses to comment on marriage rumours, saying: "There will be lots of romantic years ahead, but a wedding?We will see."

Hugh already has four children - Christie, 55, and David, 52, from his ten-year marriage to Mildred Williams, and 17-year-old Marsden and 16-year-old Cooper with former Playboy model Kimberley Conrad, to who he is still legally married.

Holly, 28, first moved into the Los Angeles' Playboy Mansion as one of Hugh's eight official girlfriends in 2001.

At present, Holly is one of three live-in girlfriends, along with Kendra Wilkinson and Bridget Marquardt. The trio of beauties star in reality TV show 'Girls of the Playboy Mansion'.