Then there's the biological clock ticking away. Not to mention financial considerations like mortgages, the high cost of children and childcare, and insurance policies for tertiary education. Add to that the practical nitty gritty of having children – do you really want your lazy Sundays starting at 5am with the patter of tiny feet? Should you start young – or wait until you're well established? Every age has advantages and disadvantages.

The energetic 20s
"From a physical point of view, the 20s are ideal," says Dr Arien van der Merwe, medical director of Health Stress and Lifestyle Management and a mother of three. "The body is young, healthy, fit and supple and it recovers fairly soon after birth. There are also fewer complications."

In your 20s, you're energetic and better able to cope with sleepless nights. Practically, you're likely to have hands-on help in the form of young, energetic grandparents. And when your children are in their teens, you'll be fortyish, and not averse to camping or waterskiing with them.

They're off your hands when you're mid-40s – leaving you and your partner free to travel or get stuck into your careers for a good couple of decades before retirement. But, hey! What of the emotional side of being a mom in your 20s? Says Dr van der Merwe: "Young women of this age are often not ready emotionally to adapt to the considerable demands of a baby.

Often, couples in a new marriage or new relationship need time to be alone together and babies can place a lot of stress on a relationship." From a financial point of view, the going can be tough in your 20s. You won't have had time to amass a nice reserve of funds and you'll probably be struggling with bond and car repayments, as well as setting up home.

The fulfilled 30s
At this age, the body is still young, supple, adaptable and healthy, if a woman has taken responsibility for her health, says Dr van der Merwe. "Infertility may be slightly increased, as are chances of genetic abnormalities."

From an emotional perspective, childbearing in the 30s is an ideal age. You are likely to be comfortable with your body, with who you are, and more settled in your relationship. A problem older moms often have is one of identity. For over a decade, your identity has been in your work. You were seen as an advertising executive or an accountant – now, suddenly, you're a mom. It's an adjustment.

You are also more set in your ways – used to a tidy house, mid-week movies and sleeping late on Sundays. Financially, this is the ideal time to have a baby. You're more established in your career as is your partner – so the chances are you'll be able to scale down your hours, work from home or be able to afford top quality home help and childcare. You should have at least 10 years of saving behind you.

The established 40s
If you have taken good care of yourself, there is no reason why you should not have a healthy pregnancy and deliver a healthy baby.

The infertility rate increases substantially after the age of 40, as do chances of genetic abnormalities. Dr van der Merwe recommends an amniocentesis for all women over 40, but only do it if you are prepared to face the possibility of a difficult decision if there are abnormalities.

Moms in their 40s have had a couple of decades to be themselves. The chances are they are well-travelled, have up-and-running careers, solid savings strategies, stable relationships and may be set in their ways. So a baby will be a major disruption and a major blessing. Many older parents say that maturity and age has given them an acceptance of difficult childhood stages, as they know that the tantrums and tears will not last forever. Others say they are short on energy and on patience.

For many 40-plus moms, a baby comes as a second family when they remarry after a divorce – often bringing with them older children and issues like jealousy and resentment. The up-side is that you have probably approached marriage with caution and your relationship has maturity and stability.