Recent studies conclude that men on average have higher intelligence than women by 3-5 IQ points. However, the ultimate evolutionary question of why men should have evolved to have higher intelligence than women remains. We suggest that men may have slightly higher intelligence than women through 4 mechanisms: (1) assortative mating of intelligent men and beautiful women, (2) assortative mating...

introduction secondary sex ratio (ssr) is the proportion of males to females at birth. it has been shown in many different mammalian species, many factors are associated with ssr. changes in secondary sex ratio in dairy cows is considered economically important and the ability to change it could affect the revenues and profitability of a dairy farm. thus, sperm or embryo sexing techniques in re...

the wild pistachio, pistacia atlantica subsp. mutica, is belonged to mountain of irano-turanian region, and distributed in northwest, northeast, center, east and south of iran. the sexual identification mechanism of this species is unknown and denotation of gender is impossible until flowering. in this study sex ratio of populations of this dioecious shrub was evaluated by several hypothesis co...