If you are thinking of having a baby, best wait until Christmas. A child conceived in December has a better chance in life than one conceived this month, with a lifetime of unhappiness, poorer prospects and lower earnings awaiting them.
A summer or autumn birth is a key determinant of a child's wellbeing and its impact may be felt long into adulthood, researchers have found.
Previous studies have shown that children born at the start of the academic year in September do better at exams than those born in August. As the oldest in their year group, when September babies start school they have a significant advantage over others in their peer group – while those born in August are younger and lag behind.
Now research by the Institute for Fiscal Studies has shown that these effects go beyond test results. Children born in August do worse in national achievement tests, are less likely to attend a top university, and are less likely to gain experience of leadership as captain of a team or chair of a club.
They also have less confidence in their academic performance and less belief in their ability to control their own destiny than those born in September. The effect was evident across social classes, suggesting that better-off families are no more able to overcome the penalties which August-born children suffer than poorer ones.
Claire Crawford, programme director at IFS and an author of the report, said: "All these [factors] are associated with a greater chance of being in work and having higher wages later in life. This suggests that August-born children may end up doing worse than September-born children throughout their working lives simply because of the month in which they were born."
The differences were evident as early as age 7, when August-born children were two to three times more likely to be judged below average by their teachers in reading, writing and maths, and at least twice as likely to report being bullied or to say they were unhappy at school.
Other studies have shown a link between being born near the start of the school year and becoming a professional sportsperson. A child born at the start of the academic year has almost 12 months growth ahead of their classmates. The researchers said there was evidence that parents strive to compensate for the disadvantage suffered by their summer-born children, by spending more time at home helping them to learn. But their efforts, it seems, cannot close the gap.
Birthday quiz: can you guess the August and September babies?
1. Hugh Grant: The foppish actor has made millions in Hollywood by playing his trademark umming and ahhing roles of light-humoured bumbling.
2. Roger Waters: Studious member of Pink Floyd, one of Britain's most successful rock bands, who were famed for the dark imagery of their lyrics.
3. John Peel: DJ who became a hero to devotees of good music and has a stage at Glastonbury named after him.
4. Ted Hughes: Married to Sylvia Plath, who later committed suicide, the Cambridge graduate and celebrated poet has been named one of Britain's best writers ever.
5. Martin Amis: Son of the similarly celebrated novelist Kingsley Amis, his critically lauded novels are outnumbered by his infamous fights and controversial statements.
6. Tony Robinson: Finished education with just four O-levels but became one of TV's most recognisable and endearing comedians in Blackadder, then turned to archaeology.
7. Howard Jacobson: Booker Prize-winning novelist and Independent columnist who secured his reputation writing about the amusing tribulations of life as a British Jew.
8. Amy Winehouse: The musician who was regarded by many as a genius for her bittersweet love songs met a tragic end earlier this year when she drank herself to death.
9. Peter Sellers: A brilliantly hilarious comic actor, he was nevertheless a notable manic depressive who suffered from drug addiction before his early death at the age of 54.
10. Roald Dahl: Entranced millions of children with his books, but often exhibited a dark edge to his storytelling.
11. Colin Firth: >Known for roles that often begin mired in melancholy yet end transformed by eternal happiness, he is the perhaps most successful British actor of his generation.
12. Philip Larkin: A poet revered as the "saddest heart in the postwar supermarket". Larkin himself said: "Deprivation is for me what daffodils were to Wordsworth."
August babies: 3, 4, 5, 6, 7, 12, September babies: 1, 2, 8, 9, 10, 11Reuse content