Gender changers, which are hardware devices, are cable adapters that can convert male connectors into female connectors and female connectors into male connectors.  A female connector is considered to be one with one or more holes.  A male connector is considered to be one with one or more plugs.

A gender changer mechanism is used by positioning it between two cable connectors of the same gender and same type.  It is basically able to change the sex of computer cables.  Gender changers can be used to test circuits and also to build specialized mechanical systems.