Cameron Diaz: I Thought I'd Be Married With 2 Kids by Age 21

Wonder why Cameron Diaz hasn't married and had kids yet? Blame Hollywood.

Although she plays an expectant mother and sports a baby bump in "What to Expect When You're Expecting," the 39-year old actress explains in the June issue of Redbook why her own life took a different path.

"I thought I was going to be married and have two children by the time I was 21. I think I felt I had to model my life after my mother's," says the star, whose mom, Billie Diaz, had two daughters with her now-deceased husband Emilio.

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"But then my career was starting to take off and there were still so many things I wanted to do," explains Diaz, who was a successful model in her teens and landed a part in "The Mask" at age 21. "So that dream [of motherhood] for me was shattered early on. After that I never put another timeline on anything in my life."

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Diaz's "What to Expect" co-star Jennifer Lopez became at mom at age 38 in February 2008 when she and then-husband Marc Anthony welcomed twins Emme and Max, now 4. The landmark how-to book that inspired the pregnancy film was a lifesaver for the singer and actress, who suffered "baby blues" after giving birth.

"I remember after the babies were born, about seven to 10 days in, I was like, 'What is going on with me?' I felt sad and depressed and thought the babies didn't love me," Lopez confessed to Redbook. "I actually remember picking up the book to try to see what was happening to me, and it said how you have this huge hormonal drop about seven to 10 days after you give birth. It's called the 'baby blues.' But I just thought they didn't like me!"

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Their castmate Elizabeth Banks became a mom for the first time in March 2011, when she and her husband, Max Handelman, welcomed son Felix via gestational carrier.

"I think the thing you always hear -- but can't really feel or believe -- is how this little baby really does change your life," the "Hunger Games" actress, 38, tells the magazine. "When you have children, it's the entire focus of your life, but my capacity for joy has been opened up in a way I never thought possible."