Sex is human sexual activity involving the bodies of one or two persons. It can be auto (meaning single) erotic, and it can be an activity between two people of the opposite sex or the same sex. This is sometimes called making love, other times it is called "babymaking". People use sex for different reasons. Sexual energy is the strongest energy in young people, for it is there to ensure that the human race does not die out. However, this energy has to be used with respect for yourself and respect for your partner or companion, be they the same or opposite sex to you.