The fact that, worldwide, there are estimated 100 million missing women as the result of gender selection is simply frightening! This is a valid issue and should be addressed by those cultures, where a preference for male children is expressed for obvious "social" reasons. Sexist gender stereotypes should not dictate who is born. In Western countries this problem does not exist. The reverse appears to be true. There seems to be a preference for a girl.
So, I believe, the problem is not with sex selection but rather with the social contexts in which it happens. If there is no obvious cultural preference for boys or girls and both genders are equal, no government regulation are needed and gender selection becomes just a matter of family balancing, free choice, prevention of X-linked diseases and ... it becomes a matter of your personal ethical choice.