As it is confirmed the Duke and Duchess of Cambridge's first child is due in July, research suggests, like all summer babies, they might not enjoy school early on but do have less chance of becoming a teenage tearaway.
Research shows summer babies, who usually start school shortly after turning four, are also 1.5 per cent less likely to go university than those born in September.
Being born in July or August can also impact on GCSE grades, with those born in these months likely to get two grades lower than a September-born pupil.
Ellen Greaves, research economist at the Institute for Fiscal Studies, said:
It is the equivalent to getting a Grade C compared to an A or two grade Bs compared with two As. It's surprising that the differences are there at GCSE age.
It may suggest that there is something happening at school. They are the youngest throughout - maybe their confidence suffers?
Ms Greaves said the think tank's research in England and Wales also showed significant differences in attainment when children were assessed at the ages of seven and 11.
"At seven, the gap (between September and summer born children) is similar to that of children born to mothers with a degree and those with no qualifications."
The differences seem to stem for having to take tests at a younger age, she said.
Ms Greaves added: "We also found using survey information that children at age seven are less likely to enjoy school if they're born in the summer months but that this doesn't continue through school."
Summer born children are, however, less likely to indulge in adolescent smoking and drinking.
"We actually found that children born in the summer months are less likely to take on risky behaviour such as smoking or drinking in their teenage years, which is a positive aspect," Ms Greaves said.
"But by the time they are 18 there is no difference."
Mumsnet founder and CEO Justine Roberts says there are also many benefits to having a baby in the summer time:
– Mumsnet founder and CEO Justine Roberts
The most common concern of parents expecting a summer baby is that he or she will be the youngest in the school year, affecting confidence and success at school," she said.
But there's no doubt it's lovely to get to grips with motherhood in the summertime - no need to worry about wrapping your baby up in multiple layers, fewer nasty bugs flying around, and plenty of opportunities to get out and enjoy the fresh air together.
Schools in England and Wales offer places to all children from the autumn term after their fourth birthday, but parents can request to delay admission.
Legally children do not have to be in full time education until the term after their fifth birthday.