This study looked at whether getting married, having children or getting divorced is likely to influence a sibling to do the same.
The analysis on more than 4,000 individuals living in Germany showed that siblings were more likely to become parents or get married if their brother or sister had done the same especially up to 3 years earlier. There was some evidence of the same being true for divorce although the picture here was less clear.
There was also some evidence of different transitions being affected with siblings less likely to get married after a brother or sister got divorced and vice versa.
The researchers conclude that sibling behaviour around family formation and break up matters for demography especially over the short term and that impacts occur within and across behaviours both positively and negatively.