Seeing Double: Are Celebrity Twins Hollywood's Latest Trend?

Jennifer Lopez, Nancy Grace and Marcia Cross have more in common than just being famous women at the peak of their careers. They have all recently become the proud mothers of twins.

Lately, Hollywood just can't seem to avoid the twin phenomenon and two more expectant leading ladies are rumored to be joining the club. This week, the National Enquirer reported that Jessica Alba is expecting twins with boyfriend Cash Warren, while Star and X17 Online have both claimed Angelina Jolie and Brad Pitt are expecting two additions to their ever-expanding brood.

[ It's Twins For Jennifer Lopez And Marc Anthony! - Watch the Video ]

The "celebrities having twins" trend seemed to gain momentum in 2004, when leading lady Julia Roberts, at the age of 37, gave birth to Hazel Patricia and Phinnaeus Walter Moder.

But Roberts and her husband, Danny Moder, weren't the only celeb parents with two diaper bags that year. Another Oscar winner, 44-year-old Marcia Gay Harden, welcomed a boy named Hudson Harden Scheel and a girl named Julitta Dee Harden Scheel.

[ Celebrity Twins & Celebrity Parents Of Twins - View the Gallery ]

Meanwhile, Dixie Chick Martie Maguire, 34 in 2004, gave birth to Eva Ruth and Kathleen Emilie. And 48-year-old Geena Davis gave birth to twin boys - Kian William and Kaiis Steven.

In 2007, the trend gained even more momentum.

[ All Access: Parenthood ]

Patrick Dempsey, of "Grey's Anatomy" fame, and his wife, Jillian, had twin boys too - Darby Galen and Sullivan Patrick. "Desperate Housewives'" Marcia Cross and her husband, Tom Mahoney, welcomed girls Eden and Savannah. And Garcelle Beauvais-Nilon and husband, Mike Nilon, welcomed Jax Joseph and Jaid Thomas.

Surrogacy seems to be a popular trend for celebrity parents, and having twins is often a likely outcome if several embryos are placed during in vitro fertilization. Dennis Quaid and wife, Kimberly Buffington, welcomed Thomas Boone and Zoe Grace through a surrogate. The twins were involved in a horrific blood thinner medication mix-up at the hospital soon after their birth.

[ It's Twins For Jennifer Lopez And Marc Anthony! - Watch the Video ]

Talk show host and former prosecutor Nancy Grace joined the twins club through surrogacy as well, bringing babies John David and Lucy Elizabeth into the world alongside her husband, David Linch.

And finally, just this past weekend, Jennifer Lopez and Marc Anthony welcomed their little boy and girl.

[ Celebrity Twins & Celebrity Parents Of Twins - View the Gallery ]

But having twins isn't just a new trend in Hollywood obstetrics. Plenty of stars themselves are twins.

The most famous twin celebrities today might be Mary-Kate and Ashley Olsen, but there are plenty of other stars who shared a womb including actors Jeremy and Jason London, and Gunnar and Matthew Nelson, of the 80's rock group Nelson.

Good Charlotte rockers Joel and Benji Madden are twins. Pop star Aaron Carter (brother of Nick) has a twin sister Angel, while Alanis Morissette has a twin brother, Wade.

Dylan & Cole Sprouse from "The Suite Life Of Zack and Cody" are twins too.

Some other celebrities with twins: Jill Hennessy and identical twin Jacqueline, Scarlett Johansson and fraternal brother Hunter, Giovanni Ribisi and twin Marissa (she's married to singer Beck), Vin Diesel and fraternal brother Paul, Joseph Fiennes and twin Jacob, Eva Green and fraternal sister Joy, Jon Heder and identical twin Daniel, Marilu Henner and twin Crystal, Ashton Kutcher and fraternal twin Michael, Isabella Rossellini and twin Ingrid, Kiefer Sutherland and twin Rachel, and Gisele Bundchen and fraternal twin Patricia.