Pregnancy is a unique experience, and there are distinct differences between twin birth and the birth of a single baby. In the womb, twins grow side by side, but their development may not always be ...

A new video out of London’s Center for Fetal Care shows twins fighting. Not that interesting? Well, it gets better because these twins haven’t even been born yet: an MRI scan shows the beginnings of ...

Seeing not one but two embryos on your first ultrasound can bring up a lot of feelings: "This was very unexpected, and I’ll admit I am scared," says one BabyCenter mom with twins on the way. "I'm 4'10 ...

A sibling can change your life, and sometimes that influence starts before birth. As part of our series on the science of siblings, NPR's Jon Hamilton explains how the sex of one fetus can affect its ...

Cinematic-MRI shows twins vying for legroom in utero. Dec. 3, 2012— -- Sibling rivalry can apparently begin even before birth and researchers in London have remarkable footage of twins fighting ...

Fraternal twins share the same womb, even though they don't share identical genes. That could be important, said Dr. John Constantino of Washington University School of Medicine in St. Louis, who wasn ...