A relationship between handedness and sexual orientation has been suggested by a number of researchers, who report that heterosexual individuals are somewhat more likely to be right-handed than are homosexual individuals. The relationship between handedness and sexual orientation has been suggested within both sexes and may reflect the biological etiology of sexual orientation; work by Ray Blanchard has linked the relationship to the fraternal birth order effect, which suggests that a man with several older biological brothers is more likely to be homosexual.