HughE: yes, I know that the most common opinion regarding mtf hrt and infertility is that you cannot guarantee that it is permanent... but I was just hoping that at least one doctor could be convinced of the opposite... and looking for him/her.
Chloe G (or Clhoe G? sorry): the motivation for the sterility requirement is not one of eugenics, but of bureaucracy. "We just can't let someone marked 'M' let have a baby! That would make a total mess in our paperwork! So, let's simply sterilize them and our paperwork problem is solved. They'll be sterile anyway because of their sex change operation." (They forgot about ovum/sperm banking...).
I live in Czech Republic, a neighbour of Germany. In 2014, the requirements became even stricter. Now, a so called "transformation of sex organs" is required beside sterilization. Basically, it puts non-phalloplasty FtMs out of the game. But it was not intentional. It happened out of pure ignorance; my father talked to the author of that part of the law and it turned it that the author was quite proud of his work in capturing the "current state", without an intention to make changes. However, he was having the idea that "every transsexual wants a sex change" and "sex change makes F genitals look like M and M like F, right?". Pure ignorance, no evil... But with evil consequences.
I'm writing to lawmaker on this matter, but the chance for change is slim, nobody cares.