A Chinese hospital has been ordered to pay 500,000 yuan (US$68,000) to two families 21 years after they took home the wrong newborn babies, media reported on Thursday.

A woman surnamed Pan, who gave birth to twin boys at a hospital in Beijing in 1986, watched as her "sons" became less alike as they grew older, the Beijing Youth Daily said.

One grew to 1.84 metres in height with strong features, the other grew into a "skinny and delicate" child about 14 cm shorter, the paper said.

After neighbours and her sons' classmates mentioned seeing a boy "exactly the same" as the older "twin", Pan took her sons to be tested. The results showed only her younger son was biologically related.

Pan eventually found her biological son in the care of another family surnamed Rao, who had delivered a baby boy at the same hospital four days before.

The two families sued the hospital after confirming that they had each taken home the other family's baby.

The court said the hospital had "lacked effective regulations governing the separation of new-born babies" and ordered emotional damages.