Zara Tindall, 36, the daughter of Princess Anne and granddaughter of the Queen, is pregnant with her second baby.

The royal, formerly Zara Phillips, is married to former English rugby player Mike Tindall, 39, and the pair have one daughter, Mia Tindall.

Mia Tindall - who is a cousin to Prince George, four, and Princess Charlotte, two - is four years old, and can now look forward to a little brother or sister.

But is Zara expecting a little boy or a girl? 

Ladbrokes told Express.co.uk it’s even money for a boy or a girl for the Tindalls currently, but that does science say?

According to research into data taken from 6,000 families, Zara is slightly more likely to have a boy than a girl.

This is because she has already had one girl.

More boys than girls tend to be born on the whole, which is thought to be an evolutionary trait developed in humans due to the fact that female babies are more resistant to disease than male babies.

A ratio of 51 per cent boys and 49 per cent girls is generally seen.

This means after you have one girl, your chances of having a boy are higher. 

After having one girl the odds of having a boy as your next child are 54.5 per cent.

However, after having a boy you have a 50/50 chance of having a boy or girl.

Interestingly, after having two girls it is more likely that you will have another.

After two little girls you have only a 46 per cent chance of having a boy.

Will Zara Tindall pick Prince Harry and Meghan as godparents? 

“It is entirely possible that the Tindalls will ask Zara's cousin Prince Harry (or even his bride-to-be) to be a godparent,” said Michael Cole, royal expert and former BBC Court Correspondent.

He remarked upon the close relationship between Harry and his cousin Zara, also known as Zara Tindall – who was introduced to her husband Mike Tindall through Harry.

“The royal cousins get on well together and appear to enjoy hanging out.”