(ABC) -- Talk about a labor of love. Susie Kozisek, an Iowa mother of four, ages 20 to 30, gave birth to her own twin granddaughters, Hallee and Hadlee.
Kozisek, 53, acted as a gestational carrier for her daughter, Ashley Larkin, because Larkin has pulmonary hypertension and cannot get pregnant. Before giving birth to the twins in July, she was also the gestational carrier for Larkin's older daughter, Harper, born in June 2011.
A gestational carrier volunteers to carry a pregnancy for another woman who cannot carry a pregnancy for herself. The eggs and sperm are harvested from the biological parents and united through in vitro fertilization. The resulting embryo is then implanted in the carrier's uterus.
"I heard about the procedure on a talk show and decided to check out the possibility of me doing this for them so they could have kids of their own if they wanted," Kozisek said.
Larkin said she considers her children a blessing and a miracle.
"I've always been close with my mom even before this so that hasn't changed and I'm grateful she will have such a special bond with her grandkids," Larkin said.