Most parents will not desire a male or female child in the sense of their genitalia. Rather, they will want a child who fulfils socio-cultural definitions of ‘boyhood’ or ‘girlhood’. This is problematic because it assumes our sex determines our adherence to gender-based social norms and behaviours.
At best, acting on assumptions which are not evidence-based is bad science. [... Furthermore,] sex selection is a product of, and perpetuates, false assumptions about gender that keep men and women “in their places”. This prevents progress towards equality and freedom from restrictive gender roles and bias.
This is simply false. In order for one's gender preferences to motivate sex selection, one needn't assume that the latter perfectly "determines" the former. It is surely sufficient for there to be a strong correlation, such that by selecting a particular sex one makes it (significantly) more likely that one's child will be of the preferred gender. And one can hardly pretend that there is zero correlation between the two -- that is not an "evidence-based" position.
It also seems highly prejudicial to assume that any parents with gender preferences must thereby be disposed to rigidly enforce traditional gender norms (let alone "restrictive gender roles and bias"!). A good parent must be open-minded and supportive of their children however they turn out, and this may well be incompatible with imposing overbearing expectations on the child that they may turn out not to satisfy. So I fully agree that "[t]he wishes of intending parents should not override the need to respect the child who will be born." But there's no good argument from this premise to the conclusion that sex selection should be banned. After all, having preferences and imposing expectations are not the same thing. Even if many people are tempted into the latter by the former, we need to be clear on where the real problem lies.
If the parents truly understand that each child is different, it becomes hard to explain why the parents seek to undergo the trouble and expense of sex selection.
"Each child is different" is not incompatible with understanding that some features (e.g. biological sex) can affect the likelihood of other features (preferred activities, behaviours, mode of dress, etc.). This should not be that hard to explain.
Finally, even if one were to accept Browne's assumption that there's something problematic about parents having gender (or, indeed, any?) preferences regarding how their children turn out, there's a big question about how one can infer any policy conclusions from this. Browne wraps up her argument as follows:
All children have a right to a maximally open future and this right is curtailed when parents expect their children to act according to a narrow set of gender norms. The stronger the parental preferences to have or avoid a child of a particular gender, the more likely those expectations will harm the child.
Only parents with particularly strong prejudice are likely to undertake such an invasive, risky and expensive procedure. As such, the risk to the child’s right to self-realisation and self-determination is even greater. As a result, the need to uphold their rights is even stronger.
Okay, let's consider the worst-case scenario of parents whose gender preferences leak over into their imposing gender expectations that may prove harmful to the child if they don't naturally fit these expectations. How is banning sex selection going to help this? Suppose the parents really want a feminine-gendered child, and will be bad parents to any child that fails to meet these expectations. (We may agree that such people shouldn't become parents at all, given the potential risks, but suppose that they are determined to go ahead regardless.) Allowing sex selection would seem to minimize the risks here, since it is more likely that a biologically female child will happily adopt feminine gender norms than that a biologically male child will.
As this example shows, one cannot in general move from "preference X is morally problematic" to "acting in ways that aim to satisfy preference X should be banned". This is especially so when what's so problematic about preference X is precisely the harms that may result when it is not satisfied!
Perhaps there's an implicit assumption in the background that the availability of sex selection would somehow make the problematic preferences and expectations more common than they would otherwise be. It would be good to see some evidence to back up this assumption, however. Perhaps one could argue that, in general, when people act with an aim to realizing a preference for X, they naturally come to form a stronger expectation of X than they otherwise would. We could call this the Act-Expectation principle.
I worry that its application here involves an equivocation. The principle seems plausible (perhaps even obvious) if we read "expectation" in a purely epistemic sense, i.e. as having a higher level of credence in X's coming about. But the problematic form of "expectation" is not merely epistemic, but involves a kind of overbearing / presumptuous / imposing behaviour. And it's far from obvious to me that such behaviour necessarily (or even probably) follows from merely acting in a way that increases the chances of X.
Especially if the agents involved have a prior commitment to refrain from such overbearing behaviour, as good parents presumably should.