When Should You Have Kids? What Science Says About Your 20s, 30s & 40s

Which decade of your life is the best to start a family? A scientific analysis can’t provide a definitive answer, but it might help you decide.


When my husband and I were planning our wedding – many years ago – we were asked if we intended to have children. We did, absolutely. We just weren’t sure when. “There’s never a perfect time,” we were warned. But is there a best age? This computer model claims it can predict when you should get pregnant, but science might also help provide the answer. So when should you have kids – in your 20s, 30s or 40s?

Your 20s

Assuming there are no underlying issues, both men and women are at the peak of their reproductive fitness in their 20s. Physically, women are in the best condition for having babies. They’re less likely to suffer from complications such as preeclampsia or gestational diabetes. The risk of their baby having a chromosomal disorder is lower.

However, younger mothers could find they miss out on developing their careers or enjoying opportunities that could benefit them further down the line. And while your body might be in prime condition for having kids, maybe your mind isn’t. Your 20s are when you party, travel and have fun. If you’re right at the start of your career, you might not want to break off to have a family.

I was 23 when I had my son (and 29 when I gave birth to my daughter). I wanted to start young, so I’d have plenty of time to get back to work and, later, enjoy life when the kids left home. But none of our friends were having kids at that age, and there’s no denying it felt isolating sometimes. We were lucky – the grandparents were willing babysitters and didn’t live too far away, so we didn’t completely lose our social lives. But it’s not surprising one study found younger fathers were more at risk of depression than older ones.

Your 30s

By this stage, you’ve probably lived a little. You’ve travelled, had your ‘wild’ years, experienced some of what life has to offer. You’re more likely to be settled into a career path. For women, that should make it easier to pick up where you leave off; sadly, we’ve all heard stories that indicate this might not be the case. Or perhaps now feels even less like the right time to take a break as you’re really starting to make your mark professionally.

It’s worth remembering that, once you hit 35, you’re officially classed as being of ‘advanced maternal age’. You may even hear the term ‘geriatric pregnancy’. This means it might be more difficult to conceive and, once you do, the chances of complications or foetal abnormalities increase. On the plus side, pregnant women in their 30s tend to find the boost to their hormones also sharpens them up mentally.

You’re more likely to feel confident you can provide a stable upbringing for your child at this age – whether you’re in a committed relationship or not. There’s also a good chance you have friends and neighbours who are parents, allowing you to share experiences, challenges and maybe babysitting duties.

Your 40s

Many women who become pregnant and give birth in their 40s without any problems. Actress Rachel Weisz was 48 when she and husband Daniel Craig – aka James Bond – announced they were expecting their first child. The number of women waiting until their 40s to have a baby is on the rise.

That doesn’t mean you should ignore the risks. Both the number – and quality – of eggs a woman has are decreasing. The ovaries are more likely to release multiple eggs in one go; are you cool with having twins or triplets? Paradoxically, though, it’s less likely a woman will get pregnant naturally. Many couples trying to start a family at this age will need assistance such as IVF. There’s a greater risk of chromosomal abnormalities, as there are more likely to be issues with the man’s sperm.

While nature might be against older parents, their experiences give them plenty of advantages. They’re likely to be more patient and have a wider perspective on life. Men experience a drop in testosterone levels, so tend to make calmer fathers than those who are younger.

And while you might not have as much energy to keep up with your energetic young child, you’re likely to be more financially stable and better equipped to provide for them materially.

Ultimately, there’s a case to be made for and against having children at every stage of life. It’s a matter of weighing up the pros and cons, looking at your own life, and deciding which is best for you. Because what our old friend said was true – there’s never a perfect time.

Whenever it happens, we adapt and be the best parents we can.

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