The law provides that the eldest male takes priority over any female, even if born earlier than the male, in the line of succession to inheriting the throne. This is up for review but amending legislation requires to be passed by various legislatures where the Queen is head of state in order to have effect. It is intended that the legislation be retrospective.
An interesting legal conundrum may arise. Assume there are royal twins, a boy and a girl. The girl is delivered first – prior to the legislatures enacting the new rules on succession. The boy will be third in line to the throne, the girl fourth, but as a result of retrospective legislation this will be reversed. The effect will be that the boy will have a number of his property rights expropriated by the state retrospectively. Could he – on reaching the age of majority – take legal action to challenge the legislation as being contrary to the ECHR?