Scientists give mice glowing sperm to monitor fertility inside the body

Japanese scientists have developed a new way to study male fertility. They’ve genetically engineered mice so their sperm glows, letting researchers observe sperm activity inside the body without needing surgery or harming the animals.

A new discovery, detailed in the January 4, 2026 issue of MedComm, was made by researchers from Hokkaido University, Osaka University, and Queen’s University Belfast, according to a report by Japan Science and Technology Agency.

Scientists have created mice whose sperm glow, allowing them to monitor fertility within the body as it happens. By using a special camera, researchers can observe how fertility changes – whether it’s declining or improving – all within the same living animal.

Scientists have created mice with glowing sperm

Traditionally, determining if drugs, radiation, or chemicals harmed male fertility involved breeding animals and then carefully examining their organs. Now, researchers at the JST have developed a new method that continuously monitors for damage without the need for breeding or dissection. This significantly speeds up the testing process and provides more accurate results.

This new technology has promising applications in areas like creating new drugs, ensuring the safety of chemicals in the environment, and researching cancer treatments. It’s particularly valuable because radiation and chemotherapy can often harm a man’s ability to have children. Furthermore, it helps reduce the need for animal testing, as researchers can track the same animal over a longer time instead of needing many different ones.

This unusual scientific study offers hope for major advancements in understanding male fertility. Researchers are using mice that naturally glow to help them with their work, and the results could be very promising.

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2026-01-13 15:50