Kevin has never minded sharing a birthday with his father. It means that no one in the family forgets the day, and there is always a big celebration with his uncles and aunts and cousins. But this year he cannot help feeling overshadowed. There is his cake with 17 candles, and beside it is his father's with... 100.

This is the age gap facing Al PacinoAn American actor, considered one of the most influential of the 20th Century.'s fourth child, due next month. But at least he or she may have a playmate in a similar situation. In May, Robert De NiroAn influential American actor, born in 1943. - who co-starred with Pacino in The Godfather Part II - told an interviewer that he had just become a father for the seventh time at the age of 79.

These announcements have provoked widespread debate about the best age to have children.

In the West, the average age of parents is rising. Since 1970 the number of fathers in the US aged 45 to 49 has increased by over 50%, while the number of those under 30 has fallen by 27%.

In the UK, the number of children born to mothers aged 45 or more rose by 72% between 2000 and 2018. During the same period the number of women under 20 having children dropped by 58%.

Traditionally, societies have been more accepting of young mothers than of young fathers, and more accepting of older fathers than of older mothers. This is largely a recognition of the fact that men can go on having children much longer than women.

A survey by YouGovA British public opinion and polling company. It was co-founded by Nadhim Zahawi, a Conservative Party politician. found that 71% of women in Britain and 60% of men thought that a man should not have a child until at least 25. At the same time, 81% of respondents thought that a woman was too old by 46.    

But medical advances such as IVFIn vitro fertilisation is a technique used to help people with fertility issues have a baby. have given a new perspective on the matter. It is now much easier for women to have babies in their forties, and even in their fifties. Meanwhile, researchers have found that the children born to men in the same age range are more likely to develop cancer or heart problems.

A key question is how age affects the relationship between parent and child. According to Amanda Jenner, an expert on child behaviour, "Older parents are wiser and more patient, and some may be more financially stable." Alan Lucas, a writer who became a father at 50, agrees: "I know I'm a much better dad than the 30-year-old version of me would have been."

But what about the children? "I would cry at night because I thought he was going to die soon," said a teenager called Vicky,¹ whose father was 49 when she was born. Because he retired when she was very young, however, she was able to spend more time with him than she would have done otherwise.

"Having an older parent does give you a unique perspective on history, and an early lesson in mortality and compassion as you see your aunts and uncles, your dad's cousins and friends at the end of their lives," said an anonymous interviewee,² whose father was 56 years older.

But, she added, the strain of looking after him in his old age "is coming awfully close to costing me my own family and career".

Yes: Being a parent requires energy which many older people lack. There is a higher risk of birth defects in children born to older parents. And the age gap makes it hard for parent and child to connect.

No: The most important thing for a child is to have a stable home. That is more easily achieved if he or she has mature parents who are established in their careers and have time and money to spare.

Or... Being too old is better than being too young. Parents who are too young may resent their responsibilities and feel that their children prevent them from living the lives they want.