Method to her salacious madness as GIRLS star LENA DUNHAM kinky past REVEALED.

IF Lena Dunham seems com­pletely at ease during her nude sex scenes in HBO’s Golden Globe-winning series “Girls,” it’s because she was raised by two sex-obsessed artists!

LENA’S DAD, CARROLL DUNHAM, produces sketches of men with male genitalia in place of their noses, while her mother Laurie Simmons has photographed everything from naked underwater ballet to Japanese sex dolls!

“Lena grew up around all this sex-oriented art, and there’s no question that it influenced the direction of her own work,” a source close to the actress told The ENQUIRER. “It was a very strange way to grow up, so it’s no surprise that ‘Girls’ features Lena naked and having sex.”

While the 26-year-old “Girls” star and creator seems comfortable with the racy content on the hit show, her childhood wasn’t always easy.

Once, after inviting some classmates to view an exhibition of her father’s work, the source reveals they taunted her, saying: “Your father paints penises!” They then stopped speaking to her entirely.

“We felt terrible, as though we’d damaged her socially,” mom Laurie has said. “She didn’t have a lot of friends in school.”

But Lena is having the last laugh now! She recently signed a $3.7 million book deal for her memoir.