Green Attendants always female in Japan?

[Joel N. Weber II]

Wikipedia's First class travel article claims:

The term "First Class" was abolished on Japanese National Railways in May 1969, and was replaced by "Green Cars". Green Cars are identifiable by the green four-leaf clover logo at the doorways. In recent years, there has been a gradual trend to restore Green Cars to longer-distance commuter lines in the Tokyo area, complete with female "Green Attendants" who provide an at-seat refreshment service as well as checking tickets.

I mentioned this to someone who was skeptical that Japanese employment laws would really allow this degree of sexist hiring, and suggested this part of Wikipedia might have been carelessly researched/written. Has anyone here spent enough time in Japan to know whether Wikipedia is accurate in this regard?