Siblings roughhousing with each other is a universal tale as old as time. And a video shows that it can even start before those siblings ever see the light of day.



According to iHeart Radio, the video from a hospital in China shows a pair of unborn twin sisters who started throwing punches in their mother's womb in December. The two are face to face before one throws the first punch and, well, the rest is fairly easy to predict.

The girls' father, Tao, said that he laughed when the nurse caught the rare moment on the ultrasound, according to the U.K Mirror: "When we saw this video, it was a big surprise to us."

Twin sisters seen 'fighting' in their mother's womb in ultrasound #NewsTrends www.youtube.com

While the video and the prenatal altercation may be cute to watch, the condition that allowed for them to happen can also be dangerous, the director of the hospital's prenatal center, told the British outlet: "It can be dangerous because it is like the twins are growing in the same 'room' when normally twins develop in two 'rooms.'"



"Monoamniotic twins," or twins who share the same amniotic sac, is a rare phenomenon affecting only a small percentage of twin pregnancies and can be very dangerous. For example, a 2013 news release from Stanford University explained, the children's umbilical cords can become entangled and cut off blood flow.

"Having a set of monoamniotic twins can be dangerous and unpredictable," Dr. Susan Crowe said in the news release. "With no membrane dividing them, the obstetrician has to balance the risk of prematurity with the risk of a cord event."

Despite the risks, the Mirror reported, the twins in this video were born happy and healthy earlier this month, and their parents have nicknamed them "Cherry" and "Strawberry."