People have long argued that the UK monarchy is discriminatory and bigoted. Quite apart from the inherent discrimination of monarchy (which excludes everyone other than the monarch from the chance to be elected head of state on their merits), the UK uses male primogeniture, which discriminates against women. As if that's not bad enough, the Act of Settlement 1701 excludes Catholics and anyone married to a Catholic from the royal succession. Now, the UK Parliament's joint committee on human rights has condemned these rules as violating the UK's international human rights commitments:
Discrimination against Catholics in the law of marriage is contrary to [article 14 European Convention on Human Rights, which outlaws discrimination] in conjunction with article 12 [the right to marriage] and also arguably contrary to the freedom of religion of Catholics protected by article nine [the right to freedom of religion] ECHR. Male primogeniture in the law of inheritance generally is in our view arguably contrary to article 14 ECHR in conjunction with article one Protocol 1.113 [which covers respecting rights].They are recommending that the discriminatory provisions be repealed, through amendments which establish a process for gaining the consent of the Commonwealth (required for changes to the royal succession). The result would be a better, less discriminatory monarchy. It would also be less appealing to the current crop of diehard protestant bigot monarchists - but that seems to be another reason in its favour.
The UK government promised to act on this issue last year, in response to a member's bill on the subject. Since then, they've done precisely nothing. Hopefully this will spur them to action.
(The Committee's full report is here)