Margaret Somerville, a distinguished ethicist, writes for the Globe and Mail in Canada:

The bottom line, regarding surrogate motherhood, and all uses of reproductive technologies, should be that when adults’ claims to use these technologies clash with the rights or “best interests” of the resulting children, the latter must prevail. So far, our decisions have been mainly based on the opposite priority. If we examine past decisions using this new basis, in some cases we might change our minds about what is and is not ethical. [source]