Instead, good policy would respect the human dignity of all persons, which means helping them to accept the body that God gave them and not upholding their belief that they are a member of the opposite sex, Pecknold said.
"Pope Francis is famous for his stress upon dialogue, and his non-judgmental approach with respect to the dignity of every person," he said. "But the Holy Father has also been crystal clear that 'gender theory' represents a burning threat to humanity, starkly describing it as a 'global ideological war on marriage'."
"The Holy Father admits that we can distinguish between sex and gender, but we cannot separate them," Pecknold said, citing the Pope's ecology encyclical Laudato Si.
"It makes much more therapeutic sense to help the mind conform to biological realities than to deform the body in order to fit a disordered mental picture."
There are also practical concerns that are addressed by not letting persons identifying as transgender serve in the military, Anderson said.
For instance, "the privacy of service members must not be infringed," he said, and this privacy could be challenged by persons of one biological sex, who identify as a member of the opposite sex, living in single-sex barracks and using single-sex showers and bathrooms.
"Given the nature of military living quarters, it is unclear where soldiers who identify as transgender could be housed," he wrote.
Allowing openly-transgender persons into the military could also pose a challenge to the religious freedom and conscience rights of military chaplains, officers, and doctors, Anderson said.
"Unless and until military leaders are able to find a way to respect all of these provisions, there will remain good reasons why the military will be unable to accommodate people who identify as transgender," he said.
Trump's announcement was met with much outrage and opposition on Wednesday and Thursday, but this is actually evidence of an almost universal disdain for natural limits set by God, argued William Patenaude, who blogs at CatholicEcology.net.
"Like it or not, the rejection of modern realities like gender theory, with its malleable understanding of the human person, is part of what Pope Francis's concept of Integral Ecology includes," he said in an article.
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Pope Francis, in his ecology encyclical Laudato Si, wrote that "the acceptance of our bodies as God's gift is vital for welcoming and accepting the entire world as a gift from the Father and our common home, whereas thinking that we enjoy absolute power over our own bodies turns, often subtly, into thinking that we enjoy absolute power over creation."
"Gender theory" rejects this belief in the natural limits of our bodies, he said, but so does today's lifestyle of excess and pollution that leads to environmental degradation.
"The laws of nature and natural law are equally fixed and render equally severe consequences when ignoring them," Patenaude said.
"And so the planet and its people suffer, all because we reject what our first parents learned in Eden. Quite often the word 'no,' is meant to protect us," he said.
Matt Hadro was the political editor at Catholic News Agency through October 2021. He previously worked as CNA senior D.C. correspondent and as a press secretary for U.S. Congressman Chris Smith.