The U.S. Central Command said two service members were killed in Jordan while defending against Iranian ballistic missile and drone attacks.
The U.S. military said a service member was killed in Iraq on Saturday during the "controlled detonation" of a downed Iranian drone, and it launched more airstrikes at Iran on Sunday in response to the killing of U.S. troops.
Those diagnosed with a deficiency have an option to undergo replacement therapy.
A new policy would require service members ages 30 and older to have their testosterone levels checked as part of routine health assessments.
The U.S. military has attacked Iran after it said Tehran struck three ships in the Strait of Hormuz.