Do girls have sperm in their bone marrow that could be used to "make a baby on their own" as is claimed on social media? No, that's not true: Sperm are not found in bone marrow. But, fertility researchers are developing methods to extract stem cells from bone marrow and use complex processes to create sperm-like cells that could be combined with an egg or egg-like cell. No published study claims this has been successfully done with human cells.
The claim appeared in a March 25, 2025 Instagram reel (archived here) under the title "Girls have sp3rms in their bone marrow and can make a baby on their own but the only result is a babygirl."
This is how the post appeared on Instagram at the time this was written:
(Source: Instagram.com screenshot)
In a March 26, 2025 email to Lead Stories, the Chairman of the Yale Medical School Department of Obstetrics, Gynecology and Reproductive Sciences corroborated what we found in searching the National Library of Medicine. "No, there is no validated or confirmed proof of sperm being found in bone marrow," wrote Dr. Hugh Taylor. He is one of the researchers in the U.S. and Japan studying the use of stem cells to allow infertile couples to reproduce. He continued:
The bone marrow is a rich source of stem cells. It is possible for many types of stem cells can be manipulated to form sperm in a laboratory. This does not happen spontaneously. It is also not perfected for use in medicine practice at this time but does have potential in the future. Of course, any sperm derived from a woman's stem cells would have only an X and never a Y chromosome. These sperm could only produce genetically female babies.
Among the studies indicating the potential of this technology is a 2024 paper in the journal Nature detailing a Kyoto University lab study (archived here) in which researchers demonstrated that mouse stem cells can be used to create egg-like and sperm-like cells. The authors of that study were careful only to conclude that their methods were indicative of future directions, not proof of a working system for humans: "In a broader context, with its capacity to provide abundant numbers (>1010 cells) of both mitotic pro-spermatogonia and oogonia, this system will be important for future directions of human IVG research."
