Someday could turn out to be very soon. Jen, who's happily with her on-again beau of nearly a year, John Mayer, 31, seems serious about getting her body into baby-bearing mode. In order to do that, Life & Style has learned, she's been frequently visiting Dr. Mary C. Kerr, the ob-gyn to the stars, who's based in Beverly Hills. "She's been seeing Dr. Kerr," confirms an insider. "She's seen her in the past, when she and Brad Pitt were together and there was talk of them trying to have a baby."
In fact, Dr. Kerr and her hubby, Wyck Godfrey (Twilight producer and the producer of Jen's upcoming movie Management), attended Jen's Feb. 7 birthday party -- where Jen seemed to follow the doc's advice of kicking back and relaxing. "I think Jen got the same advice that most Hollywood women on the skinny side get," says the insider. "Beef up, relax and give it your best."'