Tesla CEO Elon Musk has reportedly donated $10 million to a fertility and population research project in Texas, the US.

Musk has fathered at least 10 children with three women, including the pop star Grimes and a top executive at his brain-implant firm Neuralink.

The 52-year-old tech billionaire gave the money to the Population Wellbeing Initiative (PWI), a project housed at the University of Texas at Austin, through his charitable arm the Musk Foundation, reports Bloomberg.

The X owner recently funded a two-day PWI conference.

A joint programme between the University of Texas at Austin’s Population Research Center and its economics department, the PWI’s website describes it as “a network of researchers” who conduct foundational work in economics, demography and social welfare evaluation.

Musk believes that wealth is directly linked to IQ and has urged “all the rich men he knew” to have as many children as possible.

“Doing my best to help the underpopulation crisis,” Musk once tweeted. “A collapsing birth rate is the biggest danger civilisation faces by far.”

After marrying in January 2000, Musk and Canadian author Justine Wilson were blessed with a son, Nevada Alexander Musk, in 2002. Nevada died of sudden infant death syndrome, or SIDS, at only 10 weeks.

Musk and Wilson later turned to IVF. She gave birth to twins Griffin and Vivian Musk in April 2004. Griffin and Vivian are now 18.

The former couple also used IVF to welcome triplet sons Kai, Saxon and Damian in January 2006. The trio are now 16. Musk and Wilson divorced in 2008.

After two marriages to “Westworld” star Talulah Riley and a brief relationship with actress Amber Heard, Musk started dating singer Grimes in May 2018, Page Six reported.

She gave birth to their son, X AE A-XII, in May 2020. X is now 2.

Grimes revealed in March 2022 that she had welcomed his first daughter, the unusually named Exa Dark Siderael Musk, via surrogate in December 2021. Exa was given the nickname Y after their other child being named X.

Musk quietly welcomed twins with Neuralink director of operations and special projects Shivon Zilis in November 2021, according to court documents.

The newborns’ names are not yet known.