Musk Claimed C-Sections Allow Babies to Have Larger Brains?

On Jan. 2, 2024, an X user shared several graphs suggesting that younger generations have bigger brains than older generations. A year later, Snopes readers asked us to verify whether X owner Elon Musk genuinely replied to this post at the time by saying that the "heavy use of c-sections" allows modern babies to have "a larger brain, as brain size has historically been limited by birth canal diameter."

C-sections, more formally known as cesarean sections, involve a baby being surgically removed from the mother's abdomen when a vaginal delivery cannot be conducted safely.

In early January 2025, numerous social media users posted a screenshot showing Musk's alleged comment from a year earlier, including a pediatrician who said the X owner's claim was "a fabricated lie."

Musk's reply is indeed real and is still available to view on X as of this writing (archived). However, his claim has been met with skepticism from some in the scientific community.

In 2016, an article published in the U.S. science journal Proceedings of the National Academy of Sciences (PNAS) suggested that an increase in births via C-section could slowly lead to humans having larger heads. However, that article merely introduced a prediction and was limited in the evidence it used to make such a prediction. Doctors have also questioned the article and theory, noting many other reasons people give birth via C-section.

With regard to Musk's comment, using that paper to suggest that C-sections could lead to "larger brains" would be inaccurate as the proposed effect in the article mentions larger heads, not larger brains.