The birth of the royal baby boy means that three direct-descendant heirs are alive during a British monarchs reign for the first time since 1894. The newborn is third in line to the royal throne after grandfather Prince Charles and father Prince William. And if he lives to the Queen Elizabeth IIs current age of 87,he could well be on the throne in 2100 as Britains first monarch of the 22nd century,The Sun reported. Baby Cambridges place in the line of succession was assured irrespective of gender because of changes to royal rules this year. The Succession to the Crown Act,given royal assent on April 25,means first-born daughters will no longer be snubbed in favour of younger sons.