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.
Dr Anthony Atala, the institute's director, said: "We're definitely in the early stages at this point. Even though we do have these functional tissues right now, there are still many steps that need to happen before we put this into a patient. I learned so many years ago never to predict timelines because they never work out".
There are alternatives open to soldiers. British Army doctors, for example, collect and store sperm from soldiers who suffer severe genital injuries as a matter of procedure. Soldiers also have the option of having their sperm frozen prior to deployment.