Hong Kong's biological alarm clock is ringing

Mystery surrounds 'Carmen', the 67-year-old mother of newborn twins who has reignited debate about fertility treatments for older women. As we report today on the opposite page, she has sold her story to a magazine so we have to wait for more details. That has not stopped everyone from medical experts to media commentators from giving their opinion.

It would be ironic if Carmen, a name adopted to protect her privacy, turns out to have sold her story to a magazine that is part of media tycoon Rupert Murdoch's empire. She has joined an exclusive club of which he is one of the best-known members - people who become parents in their 60s or even in their 70s.

Mr Murdoch was 70 when he and his third wife, Wendi Deng, had the first of their two children. Perhaps he could counsel Carmen on coping with the physical demands of raising a child when you are old enough to be one of its great-grandparents. Presumably he would advise her to make light of the daily burden by relying on domestic help, as many of Hong Kong's busy mothers do.

The question of whether sexagenarians and septuagenarians can cope with the demands of rearing children is one of the issues on which critics have attacked Carmen. It is a reminder of the double standards applied to men and women as older parents. No one carpeted Mr Murdoch for being selfish or irresponsible, nor - to name just a few other examples - actor Harvey Keitel when he fathered a daughter at 62, nor British entertainer Des O'Connor when he said he was to be a father at 72, nor Britain's chief finance minister Gordon Brown, heir apparent to No 10 Downing Street, over having his children in his 50s.

However, Carmen has also stirred a debate that raises serious medical, biological, psychological and emotional questions about older motherhood. Older mums do have advantages, such as greater maturity and financial security. But medical experts say the optimal age to get pregnant, in the interests of both mother and child, remains 20 to 25.

Women, however, continue to shift the boundaries. The early 20s is when they have only just begun 'living' and building a career. So many of them have put back their biological alarm clock from the age of 30 to 40. In the past 10 years, the number of British women aged 20 to 29 giving birth has fallen 15 per cent, while the number over 40 has nearly doubled.

This has helped cut the birth rate and raised wider social issues, such as an ageing population in which fewer workers shoulder the burden of supporting more non-workers. This resonates in Hong Kong, which has one of the lowest birth rates in the world. It inspired Chief Executive Donald Tsang Yam-kuen, when he was still chief secretary, to call on young couples to have three children.

Prospective older mothers need to weigh the best available medical advice very carefully. But they can rest assured Hong Kong needs them.