Professor Rebecca Probert of the School of Law at the University of Warwick said:
"This announcement underlines the importance of carrying into effect long-proposed amendments to the laws governing succession to the Crown.
"Under the current rules, any daughter of the Duke and Duchess of Cambridge could only succeed to the throne if she had no brother, whether older or younger.
"The abolition of the current system of male primogeniture has been proposed on a number of occasions, and last year it was reported that David Cameron was discussing the issue with the other members of the Commonwealth.
"Following this, it was announced in the Queen’s speech earlier this year that the Act of Settlement would be amended, but so far no bill has been brought forward.
"Despite the importance of this matter, it would be unfortunate if any legislation were confined to this single point.
"Other issues that should be addressed include the current requirement that members of the royal family seek the consent of the monarch before marrying (a requirement of uncertain scope but dramatic effect, in that a failure to seek such consent renders the marriage void); the fact that those marrying a Roman Catholic forfeit their place in the succession; and the still unresolved question as to whether members of the royal family are entitled to marry in a civil ceremony."
For further comment see http://www2.warwick.ac.uk/knowledge/themes/06/royal_marriagebook