BIG Bang Theory star JIM PARSONS is preparing to start a family with his longtime boyfriend Todd Spiewak – and the pair are searching for a surrogate mother, say sources.

Parsons, 40 who plays brilliant but socially inept physicist Sheldon Cooper in the hit sit-com, and Spiewak, 36, who’s an art director, have been a couple for more than 10 years but Jim has been dragging his fee about having a child

“Todd’s wanted kids forever, but Jim said he didn’t know if he could handle the presure,” revealed an insider. But he’s very much in love with Todd and he’s finally come around.”

While the pair initially considered adoption, Jim was given a pep taslk by openly gay Neal Patrick Harris,who stars on “How I Met Your Mother,” also on CBS

Harris and his partner Neil Burtka enjoy a 3 year-old son thanks to a surrogate mother.

Said the source: “Now, Jim’s more confident he can take this major step in his life with Todd.”