Preference for boy over girl, or vice versa

Whether parents prefer boy over girl is not as obvious as it seems. Answer depends on whom you ask. Parents all over the world do prefer boys as their biological offsprings, though the extent differs from place to place. Extreme preference for boys in India and China is well documented but girls are relatively less preferred in United States too. This article (Do daughters cause divorce?) demonstrates by examples the gender bias in US.

1. Divorced women with girls are substantially less likely to remarry than divorced women with boys, suggesting that daughters are a liability in the market for a husband.
2. Parents of girls are quite a bit more likely to try for another child than parents of boys.
3. Unmarried couples expecting child are more likely to get married if the child is a boy.

Authors also find striking evidence suggesting that "boys hold marriages together, and girls break them up."

In the United States, the parents of a girl are nearly 5 percent more likely to divorce than the parents of a boy. The more daughters, the bigger the effect: The parents of three girls are almost 10 percent more likely to divorce than the parents of three boys. In Mexico and Colombia the gap is wider; in Kenya it's wider still. In Vietnam, it's huge: Parents of a girl are 25 percent more likely to divorce than parents of a boy.

Explanation seems to lie in the fact that parents (men?) prefer boys more than they do girls, and hence more likely to stick together even in failed marriage when there are male offsprings.

However, parents prefer girls over boys when it comes to adoption. Data in US shows that among adopted children, there are 100 girls per 56 boys. Adoption preference is observed in numbers registered with adoption agencies too. What is going on here?

Possible explanations, as outlined in this piece (Why do adoptive parents prefer girls?), are:

1. Parents feel that a girl is easier to understand and to rear.
2. When taking the somewhat risky step of bringing a foreign element into their family, parents might perceive little boys to be inheritors of their homes' uneasy fortunes, whereas little girls can more readily seem to be hapless victims of circumstance.
3. Boys will tend to be put up for adoption when there's something seriously wrong with them, but many girls will be put up for adoption simply for being girls.
4. Men are largely silent partners in most adoptions, indicating that men's preferences with regard to their children's gender are simply not as strong when patrimony is not an issue.

In developing country like India, people who opt for adoption are likely to be more open minded and hence prefer girls knowing that girls are more rejected and vulnerable to exploitation otherwise. In case of US, there is no consensus on which is correct explanation, but things seem to indicate that when parents have choice – which they soon will given genetic engineering and trend towards designed babies – then biases are going to raise serious ethical questions.