Well I think that you are asking entirely the wrong question, and it is for that very reason that I am firmly of the belief that religion and god should be kept entirely out of ethical discussions and politics (ha! yeah right! as if! Silly naive Flim!)
To show this, imagine I answered your question with "Yes. It would be 'playing God'; so what!?"
The questions we should be asking about matters like this is "should be allow parents to choose the gender of their child? If so, why? If not, why not? What are the potential pros and cons. Is a future going down such a path a desirable one or not?" We need to tackle the situation head on, based on its merrits not through a useless conduit of "god".
These matters are indeed vital and should be discussed in depth, without the need to resort to mystical "gods". This is too important to allow religion to mess it up.
__________________
|