Why not have it required? I guess I'm missing something.

What kind of coverage? Most insurance companies are going to keep expensive elective stuff out of their plans, so it would be pretty difficult to find a company that would offer a plan with coverage for all the counseling, medication, etc. that goes along with the transition, not to mention the follow-up. Remember, the federal employee plans are not government insurance, but private insurance offered through the government. The insurance companies like to do business with government employees, but they can withdraw if too many demands are made on them.

OK, I read the linked article. I doubt the government will try to require all insurers to cover gender reassignment surgery in all their plans because some of them would go away. The way it works now, several companies offer standard plans and "high option" plans. The high option plans cover more stuff, such as medications, optical, dental, etc. and they pay a greater share of certain medical bills. There is a wide variation in coverage from one insurer to the other, and between high and low option plans from the same insurer. In addition, not all federal employees have access to the same insurers and the same plans. It's doubtful the government could demand all insurers provide comprehensive trans-gender coverage, because they don't demand any real uniformity of coverage now. Of course, if it's a discrimination question, they would have to make exactly such a demand, and the insurers would have to decide how to respond by raising premiums, going away, etc.