President Trump admitted he didn't know about U.S. military spending on Viagra as he defended his ban on transgender military personnel during an interview broadcast on "Good Morning Britain" Monday.

Details: Show co-host Piers Morgan asked him why he felt the ban was needed, given Trump's recent tweets supporting the LGBTQ community. "Because they take massive amounts of drugs, in the U.S. military you are not allowed to take any drugs," Trump said. "You would have to break rules and regulations in order to have that."

What they're saying: Morgan pointed out the U.S. military "spends a lot more money, for example, on giving viagra to servicemen and women, well servicemen, than it does on medical bills for transgender people." The president responded, "I didn’t know they did that."

Context: The Military Times reported in 2017 the Defense Department spent $84.2 million on erectile dysfunction medications such as Viagra — 10 times more than it spent on health care services for transgender personnel.

Research by the think tank Rand Corporation showed in 2016 gender transition-related health care costs would increase the military's active duty health budget by not more than $8.4 million per year.

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