From what I have read, gender selection is ONLY available in the US for couples who already have a child of one gender and for inherited genetic disorders.
You can't just go and say you want a boy or a girl for your first child. The purpose is for family balancing.
I don't see what the problem is if a couple already has several of one gender and wants to complete their family with a child of the other gender. As long as no embyros are destroyed.
I have three sons. I don't see the problem with choosing to have a daughter next. Or vice versa. It's OK by me if it's for family balancing.