Tress Montalvo of Houston gave birth to two sets of identical twins. They’re all boys. That’s a lot of little boys. The odds of birthing two sets of identical twins? One-in-70 million. Usually in cases of multiple births, fertility drugs are involved; that’s not the case here. Besides, fertility drugs yield non-identical twins. Not that it matters one way or the other, but it’s just another point in how rare this whole situation is.