Gender stands for sex in English. A gender changer is therefore used to change the gender. Since in cable technology plugs and sockets have gender assignments - male for plug, female for socket - the term inverting adapter (gender changer) is used for plug adapters with which same-sex plugs or sockets are connected to each other.
So a gender changer is a plug adapter that connects a plug with one or more pins to another plug with the same pin arrangement. The same applies to sockets. When functioning as a male connector, the Gender Changer has a female connector on both sides. If it functions as a female connector, it has a male connector on both sides.