BRCA1 and sex ratio

Brith Sex Ratio and Pregnancy Outcomes after Bam Earthquake

Background and Objectives: Brith sex ratio could be affected by several factors such as stress due to natural disasters like earthquake. This study was performed to determine the sex ratio and the perinatal outcomes after Bam earthquake. Materials and Methods: This case-control study was designed in two sections for the evaluation of earthquake effects on brith sex ratio and the perinatal outc...

Sexuality: Sex Ratio and Sex Expression

Sex ratio, sex change, and natural selection.

We describe the analogy between the theory of natural selection on sex ratio in newborn gonochores (which will not change sex), and on the age of sex change in sequential hermaphrodites (which are all born into one sex and change to the other later on). We also discuss the conditions under which natural selection favors sequential hermaphrodites over gonochores and vice versa. We show that, in ...

Sex Ratio Elasticity Influences the Selection of Sex Ratio Strategy

There are three sex ratio strategies (SRS) in nature-male-biased sex ratio, female-biased sex ratio and, equal sex ratio. It was R. A. Fisher who first explained why most species in nature display a sex ratio of ½. Consequent SRS theories such as Hamilton's local mate competition (LMC) and Clark's local resource competition (LRC) separately explained the observed deviations from the seemingly u...

Dioxin and the Sex Ratio

The question of how exposure to dioxins might affect only males and why it affects preferentially male embryos in the Seveso data presented by Mocarelli et al. remains intriguing. This enigma can be explained by the ovopathy concept, which addresses the determination of both the sex and the condition of the progeny. Antiandrogenic properties of dioxin alter the sperm-transit time and mating beh...