The US military is funding research into lab-grown testicles for soldiers whose battlefield injuries leave them unable to conceive children.
More than 50,000 American troops have been wounded in action in Iraq and Afghanistan, the majority by improvised explosive devices.
An estimated 440 soldiers wounded in Iraq alone sustained injuries that would make it more difficult, or in many cases impossible, for them to conceive children.
Doctors involved in Pentagon-backed research at the Wake Forest Institute for Regenerative Medicine in North Carolina have used stem cells taken from soldiers to reconstruct intact testicles that have the capability to create sperm.
The most significant obstacles at present are that the testicles produced in the lab thus far have been near-microscopic in size, and it is difficult to project their long-term functionality.