Rivalries, fights over toys, different bedtimes, playing favourites and divided attentions.
It's going to be new terrain for Chinese parents who have grown up without siblings under China's one child policy - and are now being told they can have up to three children.
This comes after census data showed a steep decline in birth rates.
China scrapped its decades-old one-child policy in 2016, replacing it with a two-child limit.
Corin Dann spoke to Dr Dougal Sutherland from Victoria University's School of Psychology.
