Transcript for Mom finds out her foster baby is her adopted son's sister
Now to that "Gma" exclusive with a single mother and the stunning discovery she made about her adopted son and the baby girl she was about to adopt. ABC's Abbie Boudreau has more on this story. Good morning, Abbie. Reporter: Good morning, Michael. This story is unbelievable. Katie page knew she wanted to start a family through adoption but had no idea her journey would end with the shock of her life. ?????? Oh. Reporter: Single mom Katie page is calling it a miracle. I don't know that I believed in miracles for sure. I have no doubt now. Reporter: Newly divorced and in her 30s, Katie wanted a new life. I definitely wanted to be a mother. That was at the top of my bucket list. I had been through fertility treatments while married. My family would have encouraged me to do the perfect scenario, wait for a man. Reporter: So she game a foster parent giving temporary homes to poor children. Definitely moving forward the next placement, at least a long-term placement or foster to adopt. Reporter: Then received the phone call that changed everything. I still have a voice mail that she left me one day in the middle of work and I know it's a long shot but if you call me back we have a baby. Reporter: 11 months later Katie legally adopted her son giving him a new home, a forever mom and his name. Grayson. That was the day I got to give him a name. He had been baby boy so got legally what he deserved was a name. Reporter: Then only days later another phone call from the same hospital, about a second baby, a little girl. Abandoned by her birth mom. We potentially have an emergency placement and I want to talk to you about a little about maybe getting a second placement newborn, very little baby. Something about me telling me I'm supposed to say yes. I'm telling you god is telling me to say yes and I do not know why. Reporter: Just a few hours later Katie was home with baby Hanna in her airports. That's when she noticed the baby's hospital bracelet. I had noticed on her bracelet she was wearing the name and the mother's first name was the same as Grayson's and I was like, that's weird? Could this be true these kids could actually be related? Reporter: Katie reached out to her caseworker and within two weeks right. Grayson and Hanna were brother and sister. I was happy just to get Grayson and I thought that was big but I didn't feel like a it was enough. So to give him his sister, I couldn't imagine something better. Another strange twist of fate, Grayson and Hanna's birth mom had another baby and Katie feeling compelled to keep those sibling bonds unbroken hopes to adopt him as well. Oh, wow, Katie has a lot of love. Amazing story. Thank you for that.
This transcript has been automatically generated and may not be 100% accurate.