In conjunction with fraternal birth order, handedness provides further evidence of prenatal effects on sexual orientation, because handedness is regarded by many as a marker of early neurodevelopment. Other correlates to handedness (., cerebral laterality, prenatal hormonal profiles, spatial ability) have been linked to sexual orientation, either empirically and/or theoretically.  In right-handed individuals, the number of older brothers increased the odds of homosexual orientation, but this effect was not seen in left-handed individuals.  As with other purported marks indicating higher incidence of homosexuality, however, the link with handedness remains ambiguous and several studies have been unable to replicate it.   
Boys with too little androstenedione may fail to develop the sexual characteristics associated with puberty, including pubic and body hair, growth of the sexual organs and deepening of the voice. Similarly, girls may fail to start their periods and may not undergo many of the changes usually seen in puberty. In addition, if a male foetus has too little androstenedione,Â he may be born with abnormal genitalia. Too little androstenedione in later life would cause the same changes for both men and women as too little testosterone and oestrogen.