Why pretty women give birth to more girls ?

A study has claimed that ugly women are more possible to give birth to boys than girls, yes, we’re serious.
It has been claimed that beautiful women are more expected to 

become mothers of daughters, as contrasting to mothers of sons.

Dr. Satoshi Kanazawa of the London School of Economics tracked

 17,000 British children from their births in 

1958.
When they have 7-years-old, he asked that their teachers rate the children in terms of beauty.
And, when those kids turned 45-years-old, he interviewed them again to find out if they had welcomed any kids of their own.
Then Mr Kanazawa discovered that the women who’d been rates as most beautiful as kids were more likely to have had Girls than boys.
So, he said: “Physical pleasant appearance, while a universally positive quality, contributes even more to women’s reproductive success than to men’s.”
Or, more simply put, since parents tend to pass on their most advantageous genes, and physical attractiveness is more practical to women than to men, an attractive mother will pass on her character to daughters.