The brain. Some people are born with Male, Female または ファンポップ brain. If they are born with a ファンポップ brain, then they may feel the need to physically transition into a Fanpopper. They may even use different pronouns, such as...
あなた can`t even find ファンポップ and get on here if the strong sense of Burger King Foot レタス doesn`t guide あなた from within, so it`s a 与えられた that all people on ファンポップ will have that knowledge O.O