Parents preferring sons tend to go on to have more children until one or more boys are born, and to concentrate investment in boys for a given sibsize. Therefore, having a brother may affect child outcomes in two ways: indirectly, by decreasing sibsize, and directly, where sibsize remains...

Parents preferring sons tend to have more children until a boy is born and concentrate investment in boys for a given number of children (sibsize). Thus, having a brother may affect a child's education in two ways: an indirect effect by keeping sibsize lower and a direct rivalry effect where...