Jillian Michaels in Malibu, CA on May 20, 2012. Credit: NATIONAL PHOTO GROUP

Two times the baby joy for former Biggest Loser trainer Jillian Michaels!

Michaels, 38, recently brought home a 2-year-old daughter from Haiti after a lengthy adoption process--and a source tells Us Weekly she and her longtime girlfriend are new parents to a baby boy as well. (Michaels' girlfriend gave birth to the son.)

"It was one of those things when you put in for adoption, but she has also always wanted a baby of her own but couldn't because of health issues," the source tells Us of the fitness expert's decision to start a family with her partner.

Michaels may be new to parenthood, but her mommy instincts have already kicked in. During a May 20 farmers' market outing with her new daughter, "Jillian was very protective of her little girl whenever she would run," a witness says of the trainer and her tot, who later hit a petting zoo. "When they walked to the car, Jillian picked her up and gave her a big kiss on the cheek."