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 sibling rivalry taking place within the womb.

This advanced MRI scan is usually used to study twin-to-twin transfusion sydrome, or TTTS, where one twin takes blood from the other. It’s only been recently developed and doctors say it could be a great new tool for studying twin interactions inside the womb. Dr. Marisa Taylor-Clark of the London Center believes the benefits are extraordinary,

 

“We haven’t really been able to see before, in such real-time, complete pictures, how twins interact. What this lets us do is see their positions in relation to each other and how much space they occupy, and how they might move around and push each other out of the way, so that’s something that you can snapshots of on ultrasound, and small parts of it, but you don’t get the view of the whole room, as it were, the room being the womb.”