Can I reasonably be pro-choice but against abortion based on the foetus not being the sex you want?
No, you cannot. If you are pro-choice, you must stand for the killing of all unborn children equally, throughout all nine months of their gestation. To do otherwise is to be a hypocrite. A true pro-choice advocate will tell you that a mother should have the right to kill her unborn child for any reason at all, even if that reason is simply because her child has a vagina instead of a penis. They will tell you that it’s her body, her choice – that the body of her child is irrelevant. That her child’s body can be ripped apart in the interest of her ability to choose.
Choice: the greatest euphemism ever created for human slaughter. Embrace it.