China’s top legislature has sanctioned the ruling Communist Party’s decision to allow couples to have a second child if one parent is an only child.

It’s the first major easing in three decades of the restrictive national birth planning policy.

Implemented around 1980, China’s birth policy has limited most couples to only one child, but has allowed a second child if neither parent has siblings or if the first born to a rural couple is a girl.

The official Xinhua News Agency said the standing committee of the National People’s Congress approved a resolution on Saturday to formalise the party decision.

It says the national lawmaking body has delegated the power to provincial people’s congresses and their standing committees to implement the new policy.