During the intense push to get don't ask, don't tell (DADT) repealed, I was happy to lend my voice to the effort. It was somewhat personal – I had served with gay troops in Iraq and saw no ill effects on unit cohesion, whereas we desperately needed more Arabic linguists and I knew several had been kicked out of the Army not long before the invasion. And it was somewhat driven by a sense that discrimination based on sexual orientation is fundamentally wrong, and that forcing gay troops to lie about something so intrinsic to their lives was a violation of military values.

Not long after the repeal was signed into law, I saw a few scattered voices saying rights for transgender troops was the next issue to tackle. I was resistant for several reasons. For one, it seemed important to lay concerns that DADT repeal would cause problems to rest before pushing on an issue many are even more uncomfortable with. Also, allowing women to serve in ground combat arms jobs and units had higher personal importance to me based on my own background, and – to be quite honest – I shared some of the discomfort and concerns about transgender issues, about which I knew little.

Recently, I attended an event on Diversity and Inclusion Best Practices for US and European Militaries hosted by the German Marshall Fund. Hearing the perspectives of our allies on a variety of topics was fascinating and eye-opening. At one point, an American asked one of the panels how they handle transgender personnel and any associated issues. The response from members of several foreign militaries was confusion about why there would possibly be a problem with allowing transgender people to serve. (Countries including Spain, Australia, Israel, and Canada allow transgender troops to serve openly; the United States does not.)

A couple mentioned that if people were going through gender reassignment, the policy is to wait until the process was complete before allowing them to serve. Panelists offered examples of senior officers who are transgender. In the UK, where trans people have been able to serve openly since 1999, it was "no big deal" when a pilot transitioned to become a woman a few years ago. In fact, from what I can tell, when the Ministry of Defence issued its formal Policy for the Recruitment and Management of Transsexual Personnel in the Armed Forces, the only controversy it caused was whether it was a waste of money to develop and issue a formal policy.

Here in the US, this year a former member of Seal Team 6 came out as transgender. Discussions about Chelsea Manning's gender identity swirled in the media (to the chagrin of some trans soldiers). Some universities are asking students to chose which pronoun they prefer. And on a personal note, I was privileged to meet a retired Army officer, a Vietnam veteran with a proud post-military career in intelligence and business, also a devoted husband and loving father, who happens to be a cross-dresser. She was kind enough to help me understand more about the transgender spectrum.

This confluence was eye-opening for me and forced me to reflect carefully on my own reluctance to advocate for barrier-free transgender military service as I had for women and gays. I was forced to admit that if I didn't root out some of my own prejudices, my children would likely look at me someday and ask how I could possibly hold such outmoded beliefs. Just as my parents' generation was embarrassed by the racism of their parents and many in my age group have been mortified by the widespread homophobia in our parents' cohort, this will likely be the next example of a bias that society struggled to overcome.

I am now completely confident that our military could successfully navigate any challenges that arose. Americans regularly praise our troops as the most professional in the world. Arguing that they wouldn't be able to handle serving with openly transgender colleagues while the UK and many of our other Nato allies are easily doing just that impugns the honor of our service members.