Her biological clock may be ticking louder than ever, but it appears Jennifer Aniston's going to have to listen to it a little longer. Contrary to recent reports suggesting she's pregnant, Jen's not, her rep insists. But the Marley & Me star, who'll turn 40 on Feb. 11, refuses to give up on her dream of being a mom, telling Vogue, "I've said it so many times. I'm going to have children. I just know it." Having reconciled with on-again boyfriend John Mayer, 31, Jen may be one step closer to finally starting the family she's always wanted.

But while John's looking more and more like a promising daddy candidate, reports that Angelina Jolie, 33, may be pregnant again (which her rep denies) can't be easy on Jennifer. Even if Angie isn't expecting, she's made it clear that she and Jen's ex, Brad Pitt, who welcomed twins Knox and Vivienne in July, plan to add to their brood. "It's chaos in our house, but it's so much fun," a gleeful Angelina,recently exclaimed. "We'll definitely have more."

Meanwhile, on Nov. 20, Ashlee Simpson-Wentz, 24, and hubby Pete Wentz, 29, welcomed their first child, a boy named Bronx Mowgli Wentz. The baby, who weighed in at 7 pounds, 11 ounces, is already being showered with love by his parents -- and his famous aunt. "Bronx is beyond precious," Jessica Simpson gushes. "I'm over the moon. Life is a beautiful miracle."

For more on Hollywood's baby boom, pick up the latest issue of Life & Style, on newsstands now!