Sex"u*al (?),a. [L.sexualis,fr.sexus sex: cf. F.sexuel.]Of or pertaining tosex, or the sexes; distinguishing sex; peculiar to the distinction andoffice of male or female; relating to the distinctive genital organsof the sexes; proceeding from, or based upon, sex; as,sexualcharacteristics;sexual intercourse, connection, or commerce;sexual desire;sexual diseases;sexualgeneration.

Sexual dimorphism(Biol.),thecondition of having one of the sexes existing in two forms, orvarieties, differing in color, size, etc., as in many species ofbutterflies which have two kinds of females. --Sexualmethod(Bot.),a method of classificationproposed by Linnæus, founded mainly on difference in number andposition of the stamens and pistils of plants. --Sexualselection(Biol.),the selective preference ofone sex for certain characteristics in the other, such as brightcolors, musical notes, etc.; also, the selection which results fromcertain individuals of one sex having more opportunities of pairingwith the other sex, on account of greater activity, strength, courage,etc.; applied likewise to that kind of evolution which results fromsuch sexual preferences.Darwin.

In these cases, therefore, natural selection seems tohave acted independently ofsexual selection.