The Centauri, while seemingly human in outward appearance, Centauri have a very dissimilar genetic structure. The most pronounced difference between the two races are their sexual organs. Male Centauri have six "tentesticles" which can be manipulated with great skill. They extend out from the sides of the body and "fold" in over the solar plexus when not in use. Centauri females have six narrow receptive orifices, three on either side of the base of the spine, just above the hips. Centauri sexual intercourse can be divided into levels of intimacy and pleasure simply from the number of tentesticles used in penetration. Culturally, the use of only one tentesticle is of little significance since only mild stimulation occurs (though fertilization is entirely possible unless steps are taken to prevent this). The more tentesticles used, the greater the pleasure for both participants.