Preconception gender selection: a threat to the natural sex ratio?
نویسندگان
چکیده
منابع مشابه
Natural Selection: Sex Ratio
Natural selection acts strongly on the proportional numbers of male and female offspring among the progeny of adults. The equilibrium is often one at which males and females are produced in roughly equal numbers, but under certain ecological and genetic circumstances there may be dramatic population-wide biases, and even in populations with balanced sex ratios, parents are often selected to pro...
متن کاملSex 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 ...
متن کاملMaternal preconception diet and the sex ratio.
Temporal variations in the sex ratio, or the ratio of boys to girls at birth, have been widely studied and variously attributed to social changes, conditions of war, and environmental changes. Recently, Mathews et al. ["You are what your mother eats: Evidence for maternal preconception diet influencing fetal sex in humans," Proc. R. Soc. bond. B 275:1661-1668 (2008)] studied the direct evidence...
متن کاملPreconception gender selection for nonmedical reasons.
For centuries, attempts have been made to choose the gender of offspring, but not until the 1970s did effective prebirth gender selection become possible through prenatal diagnosis and abortion. More recently, preimplantation techniques to determine the sex of embryos for transfer have been established (1, 2). Because these methods require either prenatal diagnosis and abortion or a costly cycl...
متن کاملSex 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...
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ژورنال
عنوان ژورنال: Reproductive BioMedicine Online
سال: 2005
ISSN: 1472-6483
DOI: 10.1016/s1472-6483(10)62218-3