Dillon was reportedly born at 1:42AM, weighing eight pounds and 10 ounces. He was 20 1/2 inches long, according to the magazine.
Anderson became a new mom two months after she announced she's divorcing the baby's father, Sam Poueu.
"It is with great sadness that my marriage to Sam Poueu is ending," Anderson, who was seven months pregnant with the couple's first child at the time, said in a media statement released in May. "Thank you in advance for respecting our privacy during this difficult time."
While Anderson failed to disclose any reasons behind the sudden split, People subsequently reported it was because Poueu had been cheating on his wife for the majority of their relationship.
"Stephanie felt they weren't connecting and decided they should go to counseling. It was getting dire," a source told People that same month.
"In one of the counseling sessions, Sam thought he would make it better by confessing. He [admitted] that he had cheated on her with multiple women throughout the course of their courtship and marriage. He told her everything."
As a result of Poueu's alleged confession, "Stephanie decided to split."
When contacted for a statement, Poueu didn't deny the source's infidelity claims.
"The circumstances and specifics of our marriage and our separation are extremely difficult and private," Poueu told People, adding that Anderson's pregnancy was the couple's priority at the time.
Poueu, 28, and Anderson, 33, have yet to formally file for divorce but are in the process of doing so, their representative told Us in May.
Poueu and Anderson met while filming The Biggest Loser's ninth season in 2009, and then Poueu proposed to Anderson during an episode of the NBC reality weight-loss competition which aired in October 2010.
However, Poueu tragically fell four stories down a fire escape and was hospitalized in critical condition in September 2011 -- resulting in a months-long and intense rehabilitation process.
The couple then got married in April 2012 in San Francisco, CA.