BRUSSELS — Belgium has built a reputation as among the most progressive EU countries on trans rights. For the past five years, people there can legally change their gender and name without medical certification. Its current government includes a transgender politician in a leading position. And, just recently, the city of Ghent in Belgium’s northern Flanders region polished those progressive credentials by granting city officials a month of leave to undergo gender transition. Vlaams Belang or “Flemish Interest,” a separatist party that dominates Flanders, has been leading in polls. The party has expressed concern over a “growing trend of minors identifying as transgender” and called for “hormone therapy and sex surgery to be halted for underage patients until clear and concrete research has been carried out.”