Jemma Kinderson was born into post apocalyptic earth, where the population of women had decreased rapidly after a scientist gone mad created a syrum. That was intended to be the answer to overpopulation, but instead destroyed the reproductive system of women, only those who didn't take it were saved. Jemma's mom did take it but instead it gave Jemma blessed fertility, which meant she was able to have multiple children at once, and it would last until her dieing breath.