The rules of male primogeniture were once the general rule.  The closest male relative to the deceased inherited everything.

The titles of nobility in Britain still follow the old rule.

This does not please the Earl of Balfour, who has been an outspoken critic of male primogeniture. It is perhaps because he does not have any sons, but does have four daughters.

His daughters cannot inherit his title and it is set to pass to his younger brother, when the Earl passes away.

A proposed new law, which has the support of Prime Minister Theresa May, would allow British citizens to change their gender.

The Earl of Balfour suggests that one of his daughters could use the law to inherit his title.

It is not clear if he is actually suggesting that one of his daughters would go to that length to get around the strict rules of male primogeniture.

Reference: Daily Mail (Nov. 29, 2017) "New gender laws could let my girls inherit title, says Earl: Aristocrat suggests one of his daughters could identify as male after his death to claim his title."