In the gametophyte form of mosses, reproduction is generally sexual and is seasonally controlled. Male sex organs known as antheridia and female sex organs, which are referred to as archegonia, are typically located at the tips of the main shoots of gametophyte mosses. Whether shoots are unisexual or bisexual is a species dependent characteristic, but many mosses are designed to discourage inbreeding. The reproductive process itself can only take pace when the plant is wet, sperm released from antheridia swimming to female archegonia to penetrate ova and create a zygote.