Defending the de dicto approach to the non-identity problem

Is it wrong to create a blind child, for example by in vitro fertilization, if you could create a sighted child instead? Intuitively many people believe it is wrong, but this belief is difficult to justify. When there is a possibility to create and select either ‘blind’ or ‘sighted’ embryos choosing a set of ‘blind’ embryos seems to harm no-one since choosing ‘sighted’ embryos would create a different child altogether. So when the parents choose ‘blind’ embryos, they give some specific individual a life that is the only option for her. Because her life is worth living (as blind peoples’ lives are), the parents have not wronged the child by creating her. This is the reasoning behind the famous non-identity problem. I suggest that the non-identity problem is based on a misunderstanding. I claim that when choosing a ‘blind’ embryo, prospective parents harm ‘their child’, whoever she or he will be. Put another way: parents harm their child in the de dicto sense and that is morally wrong.