Being almost 9 months pregnant and 40, I feel I must add my two cents to this discussion:
It is true that pregnancy at a later age carries some health risks, from it being more difficult to conceive to possible genetic issues with the baby, such as down syndrome. However, in this day and age, those problems can often - though not always - be overcome. I had my son 18 months ago when I was 39 and am expecting a baby girl in January. Both were conceived without difficulties (in fact this second one came around rather more precipitously than was planned /blushing.gif' class='bbc_emoticon' alt=':blushing:' /> ). They do routine screenings for birth defects and genetic issues and you can also have tests like the CVS or amnio which give you pretty much 100% reliable screening so you can have peace of mind (these are mandatory in the US, where I live they are elective).
As I didn't have kids earlier, I can't compare my energy levels for running after them and coping with the whole delightful experience to those of a 25 year old. It is probably true that my partner (he's 46) and I are less fit, need more sleep and generally not as physically robust as younger parents. On the plus side, I have years of sleep deprivation training working as a lawyer in a large international law firm, which is very handy! Joking aside, I am more conscious of my health now and hoping I can keep fit and healthy enough to see my little ones at least into their early '20s - again a concern that a younger parent probably doesn't have.
Having kids older though has some important advantages too: I am much more financially settled than I was in my '20s and can afford excellent childcare + someone to clean my house which helps; I have had a longer time to enjoy the carefree single life, travel, party, "sow wild oats", whatever so I don't feel like I'm sacrificing much when I stay home on a Saturday night or don't go to that exciting trip or whatever; I had devoted my 100% to my career for the past 15 years or so, so now I feel like I am entitled to take it a bit slower and have a decent amount of "good will" accumulated at work so that I don't need to be embarassed about taking 2 maternity leaves in as many years; also, by the time I finally got them, I was also 100% sure that I did want kids and maybe apperciated the experience more than a younger parent.
That said, Mandy, I am most definitely stopping at 2 and can't even imagine contemplating a 4th!
Edited by MrsManderly, 11 December 2012 - 01:48 PM.