The famous Hollywood couple resorted to fertility treatments to promptly conceive Knox and Vivienne, a source tells Us Weekly.
The source extremely close to Angelina Jolie and Brad Pitt reveals, “They conceived through in vitro fertilization. They both desperately wanted more babies soon.”
According to Dr. Arthur Wisot of L.A.’s Reproductive Medical Group, who isn’t at all involved with Jolie and Pitt’s in vitro procedure, “We live in an era of reproductive freedom, so anybody can do anything they want within legal limits.”
The understanding is that the likelihood of Jolie conceiving fraternal twins through the natural process at age 33 is under 1 percent. But through in vitro, Jolie’s chances shot up to 25%.
Jolie opted to undergo the procedure, which reportedly can “cost around $12,000 a pop,” so “she wouldn’t have to deal with the stress of trying to get pregnant. She could just knock it out,” the source tells Us Weekly.
In an interview with Elle U.K. last year, the actress hinted about producing as many kids as possible. “If we’re going to have 10 kids, we’d like to raise them while we’re young.”
The source adds that Jolie and Pitt, who turns 45 on December, “were too impatient.”
[Source]

