Sex in Man and Animals

100 females ABCDE AbCdE aBCdE advantage antlers become Bonellia boys breeding season bright colours castration chapter chevrotain colour-blindness concerned contraception copulation copulatory organ divides effect embryos evolution fact factors female-producing fertilized eggs flatworms formed freemartin fuse Gametes GB GB GB germ cells girls glands gonads groups grow GYNANDROMORPHISM halved number hermaphrodite higher animals individual inherited intersexes large number male and female male sex mammals mankind many-celled animals marriage mated matter moiety mother natural selection normal nucleus number of chromosomes number of males offspring ovariotomy ovary pair of chromosomes Paramecium parent parthenogenesis polar body primitive probably produced promiscuity race reason Red-eyed female reducing division reproductive organs result secrete sex characters sex chromo sex chromosome sex determination sex ratio sex-intergrade sexual abnormality sexual characters sexual instinct sexual reproduction sexual selection single-celled animals species sperms sperms and eggs takes place testicular testis theory THREADWORM tissue tube types of sperm women