According to a US Weekly, New parents Angelina Jolie and Brad Pitt resorted to fertility treatments when they decided to have more children.

"They conceived through in vitro fertilization," said the Weekly. "They both desperately wanted more babies soon," and actress, 33, chose the $12,000 procedure so "she wouldn't have to deal with the stress of trying to get pregnant. She could just knock it out."

Fraternal twins Knox Leon and Vivienne Marcheline were born on July 12 at a hospital in Nice, France to join siblings Shiloh, 2, Zahara, 3, Pax, 4, and Maddox, 6.

The star couple has spoken about a desire to have several more children. Jolie said on "The Daily Show" last year that she and Pitt can't decide how many children they want. "It fluctuates between seven and 13 or 14," she said. "We kind of feel like, damn it, we're up for the challenge."

Dr. Arthur Wisot of L.A.'s Reproductive Medical Group, who did not treat the couple, told US Weekly that "we live in an era of reproductive freedom, so anybody can do anything they want within legal limits."