Is there an expected relationship between parental expenditure and sex ratio of litters or broods?

► Trivers-Willard predictions on sex ratio may not apply to broods. ► We model adaptive parental decisions on offspring sex for litters/broods. ► Increasing parental resources may increase sex ratio if brood size does not vary. ► If brood size varies, parental resources may be negatively related to brood sex ratio.