Sisters' Late Babies Might Help Brothers Live Longer

There's a fascinating link between sisters having babies later in life and their brothers living longer. This isn't about lifestyle choices but likely about genes.

Key Findings

• Women who have children in their 40s and 50s without fertility help tend to live longer after menopause.
• Brothers with three or more sisters, including at least one who had a baby at 45 or older, were up to 22% less likely to die after age 50.
• The brothers' wives didn't see the same benefit, pointing to genes as the key factor.

Research Details

Researchers studied two large groups:

• 1.6 million Utah Mormon pioneers and their descendants
• 400,000 people from Quebec

In both groups, birth control and fertility treatments weren't common.

Women Living Longer

• Utah pioneer women who had their last baby between 41 and 44 cut their risk of dying after 50 by 6%.
• Having a baby at 45 or older reduced that risk by 14%.
• Similar patterns were seen in Quebec.

Trends in Modern Times

• In 2020, nearly 1,000 American women aged 50 or older gave birth.
• Some women even have babies in their 60s.
• The average age of first-time mothers in the US was 27.5 in 2023, up from 21.4 in 1970.