Originally Posted by GQgeek
This is most certainly a case of finding the result that you're hoping to find....
Factors such as mother's health/previous pregnancies and father's age can cause developmental problems in the womb and at conception itself, respectively. Hence, the expression "the runt of the litter."
That doesn't necessarily mean that the firstborn will be the healthiest and therefore the largest and, more so for males than females, the most physically attractive. For example, a very young mother is at risk for certain problems. Or a mother could learn from experience to take better care of herself while pregnant.
Also, the book suggests that how a child is treated by parents impacts his or her future achievement. You know what? One frightening fact is that, on average, parents treat their better-looking children better than their less attractive siblings. (The youngest can also be in the aesthetically favored role, because children often become less attractive as they develop.)
The fact is only shared because it's believed that many Style Forum members have young children or will soon have them and are appearance-conscious and adequately self-aware to fight the instinctive bias.