Conditions May Favor Boys vs. Girl Embryos

Avatar for Cmmelissa
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Registered: 11-13-2008
Conditions May Favor Boys vs. Girl Embryos
Fri, 12-28-2012 - 3:53pm

I thought that this was some interesting research onto why female vs male embyros don't always have the same chances at survival in the womb: 

The discrepancy could theoretically be explained by differential fertilization efficiencies of male and female sperm (Y chromosomes are smaller than X chromosomes so perhaps male sperm can swim faster?) or by different rates of survival of male and female foetuses in the uterus. Indeed, it does seem as though male embryos are better able to survive under conditions of high energy intake. But how does this work? 

Jana Beckelmann in Christine Aurich's laboratory at the University of Veterinary Medicine, Vienna now presents provocative evidence that a particular protein, insulin-like growth factor-1 or IGF1, might somehow be involved. From an examination of about 30 embryos, Beckelmann noticed that during early pregnancy (between eight and twelve days after fertilization) the level of messenger RNA encoding IGF1 was approximately twice as high in female embryos as in male embryos. 

You can read the full article at:

From what I understood from the article, this protein helps a female embryo survive in a womb that would favor a male embryo.   It makes me wonder what the environment is in my own body that made it more favorable to boys rather than girls, what do you think about it?