It won't be news to young parents suddenly saddled with a brood of kids, but Finnish researchers have just scientifically established that our 20s are the social high-water mark that we'll never see again.

The research, just published in Royal Society Open Science, confirms that 25-year-old men have the most social connections and that our social circles shrink thereafter.

Mobile phone records were used by the researchers to show that, in our 20s, men are more socially connected than women, but men lose their mates so rapidly that, by the age of 39, women have the most social connections, and this continues into old age.

The authors say this may be down to women being better at keeping in touch with their kids and grandkids.