I try not to judge, and I can see why people do it, but I do think having babies much older than 40 is really not a great idea for the health risks to the baby alone, aside from the issues that come with having older parents. My cousin's mom just had a baby at 47, and thankfully he's so far healthy....but...when he graduates HS his mom will be going on 60. Otherwise personally.....I did want to have babies young (not this young!), and thought I'd start trying at 24 or 25 (also thought it would take a long time for me to conceive). I keep saying I don't want to have any babies too far into my 30s (I think 32 would be the latest I'd want to give birth, so essentially if I was pregnant at 31, I'd stop trying). I wanted a couple of kids, and I'd love for Lilly to have a sibling really close in age, but right now isn't a good time, and I also don't want kids 3-4 years apart, so I'll wait until she's 4 to even start trying...I'll be 28. I could try to cram two in between 28-30, but IDK. I have at least 2 more years of undergrad, and I can't see trying for another one before then. I guess I could change my mind about the age difference thing. For the general world population (or at least present day American/Canadian/Similar society-ians)...somewhere between 20-40. When they're healthy and ready and able to care for their children. Everyone's different. If I'm not ready for another kid before 31, the current plan is to have no biological children and just do foster care or adopt a slightly older child.