Ironically, numbers were quite even during the first year, but then Sega did exactly the same thing every other asian MMORPG does:
CEO: Alright guys, populations are quite even, now and for the next 10 or 20 gachas, release nothing but female costumes and accessories and leave males with 1 boring, clipping costume noone will ever want per gacha tier.
PLAYERS: Screw this, i am going to play Female, they are cuter and can be customized much more.
CEO2: Welp, i guess this means people only want to play females, keept it up, people!
Male Player: But what about us?
CEO&CEO2: Yeah well, market studies have clearly shown that female characters are more profitable, so sadly we will have to focus most of our efforts in Female fashion from now on and towards the future.
This was true when i worked in the industry and it is true today.