LB – it is POSSIBLE that it is a problem to daven that that child be a girl. I am not sure, so ask a sheilah.
It is POSSIBLE that it is permissible to daven that you have a girl (even while you are expecting) as long as you don’t daven about that specific baby. Again, ask a sheilah.
It is also possible that it depends on whether or not you were already mekayem p’ru u’rvu (meaning that you already had one boy and one girl or 2 boys and 2 girls). Again, I don’t know, so ask a sheilah.