If you are rich enough, you will be able to circumvent the prohibition and obtain the right to select the sex of your child. The Human Fertilisation and Embryological Authority bans the practice here, though their grounds are weak:
Britain’s Human Fertilisation and Embryology Authority remains cautious, citing public opposition to sex selection. “In the US there is no official regulator to monitor clinics and no legal obligation to offer the counselling that is an important part of treatment,” a spokesman said. “Those who choose to go overseas for their treatment should make themselves aware of the laws and consider what impact there may be on any child that is subsequently born.”Public opposition is cited, alongside a nannyish presumption of in loco parentis. Public opposition is not a sufficient reason for curbing reproductive freedoms and gives a veto to lobbies who invoke the 'yuck' factor. The HFEA model of regulation never succeeded and medical practices should be allowed, except in cases of safety.
If Parliament wishes to outlaw a reproductive technology,then let it do so: otherwise, the presumption of freedom should prevail.