That right there is 100% false.
A person can have a double pregnancy which is referred to as superfetation that can only occur under a couple of specific circumstances. Superfetation is rare and may only happen in one out of a few million pregnancies; and it's thought that there are fewer than 10 cases reported in medical literature. Superfetation can only happen under a few specific circumstances: when a woman either has a double uterus, or if she ovulates multiple times, and the second egg gets fertilized.
**California woman who carried a couple’s child as a surrogate also got pregnant with her own biological child after she was already pregnant.
In a separate account, an Australian woman had "twin" girls who were actually 10 days apart in age because she was pregnant with two babies at the same time. Oh, and a woman in Bangladesh with two uteruses delivered one baby normally and then—wait for it—twins 26 days later, via C-section.