STUDY QUESTION Does embryo culture medium influence the percentage of males at
birth? SUMMARY ANSWER The percentage of males delivered after ICSI cycles using G5™ …

The secondary sex ratio (SSR), indicating the ratio of male to female live births, has
garnered considerable a ention within the realms of reproductive biology and public health …

Based on evolutionary reasoning, Trivers & Willard (1973) predicted status-biased sex
composition and parental investment with son-preferencing effects in higher, and daughter …

Within current theories on potential adaptive manipulation of offspring sex ratio, giving birth
to a male or to a female is assumed to depend on the capacity of the mother to invest in …

Females of many species can gain benefits from being choosy about their mates and even
exhibit context-dependent investment in reproduction in response to the quality of their …

Background and objectives The sex ratio of human birth cohorts predicts the health and
longevity of their members. Most literature invokes natural selection in support of the …

The research explores the effects of the environment on neonatal mortality in the early
nineteenth century, controlling for social and economic factors. Individual data, relative to the …

AIMS: Fallout from atomic bomb testing may travel great distances before precipitating.
Males are born in excess of females in a ratio that approximates 0.515 (M/T: male live births …

We consider the effects of major prenatal economic shocks experienced by mothers on two
indicators of newborn-infant health, birth weight and head circumference, using detailed …

Given an equal sex ratio at conception, the excess of human males at birth can only be
explained by greater loss of females during pregnancy. It is proposed that the bias against …