My Mom was 45 and Dad was 41. I did not have granparents because they had passed before I was born.
I have a nephew hat is 6 months older than me. My parents could not be grandparents to my brother and sisters kids because they were raising kids.
My mom passed when my oldest was 2 years old, and my dad passed when my youngest was 4 years old. My boys did not get to know one set of their grandparents.
My father in law taught me how to be a grandparent.
My father was 44 when I was born. He died when I was nearly 18, and his health started failing when I was a little kid. I never knew him when he was healthy and robust.
There aren’t any rules-of-thumb because every situation is different, but purely on health grounds I’d say 35 for the mother and 40 for the father, and even that is pushing your luck. I have a chronic health condition which I partially blame on the fact that my parents were over those ages when I was conceived.
It’s possible for older parents to have healthy children, but the chances are lower, and I wouldn’t care to gamble with human lives. All the love in the world can’t cure fucked-up chromosomes.
Well my dad was 45 when I was born so I do not see any problem.
‘Pulling it off’ = ‘getting pregnant and having a baby’.
Having a biological child is a selfish desire in every circumstance. IMO. And you can’t really guarantee that you will be able to provide for them optimally, no matter your age or circumstances when you first have that baby. Shit happens.
I do think it’s wise to be aware of age when it comes to parenting. I just don’t have negative judgment for people that decide to have the baby even though the father is older.
I guess I don’t really think of aging the way you seem to. In my family and my boyfriend’s (who I am closer to) people are generally extremely spry until their mid 80s at least (unless they’re randomly killed or disabled in their relative youth). 60-something when your kid is 18, doesn’t seem that old or likely to be infirm, to me.
I happen to know a lot of people with dads who were 45+ when they were born. Including my boyfriend, his mother, my father, whose bio parents were 45 and 50-some, and my mom - her dad was 49 and 51 when his last two children (one of them my mom) were born, he was a very active father and in great health all his life, and he’s still kicking today at 98 years old, with most of his grandkids self-supporting, and two young great-grandchildren. It very rarely seems to be an issue.
If you’re going to be in diapers before the kid is out of them, you’re too old. 
I adopted the Firebug right around my 55th birthday, when he was a year and a half old. Now he’s nearly 4, I’ve got no complaints, and I don’t think he does either. I know I’ll be 71 when he graduates from high school, but based on my parents and grandparents, I should still be in very good shape at that age if I stay active - and that shouldn’t be a problem!
I do wish there would be two or three decades, rather than maybe one, between the beginning of his adulthood and my inevitable senescence, but this is the best ride I’ve ever been on, and when making the choice between ‘late’ and ‘never’, I’m extremely glad I chose ‘late’.
my 29 year old sister just told me she is pregnant- the baby daddy just turned 60. I suppose it’s ok if he doesn’t live long enough to see the kid graduate because keeping men and baby daddies around in her life / the kids’ lives doesn’t seem to be of importance to her anyway.
Actually, I’m 31 and I only just lost my last grandparent two years ago, even though my parents were 39 and 49 when they had me. I know plenty of people who had fewer grandparents than I did but much younger parents.
My dad was 55 when I was born. He died when I was 12. I have yet to receive any cognitive abnormalities from his so called “senile mutant sperm,” but well, the night is young as they say!
I’d say that the cutoff would be whatever age where it becomes more likely than not that you will not be around for another 18 years.
I would generally agree that’s it’s probably not the best idea to go around making babies when you’ve got one foot in the ground, but there are always fabulous exceptions. My pop should have been dead long time ago, and had already exceeded his life expectancy by the time I turned 18 by several years. He turns 90 this October. Go, Dad, Go!
Hopefully more than 40. When we started the adoption paperwork, my wife and I were 32. Now we’re 38 and still in the queue. Should happen within the next year or so.
I had my first son when I was 29.
I had my second son when I was 40. LittleDivine is now 8, and I do notice that the moms of his classmates seem a little younger than me, but not significantly so.
As an experienced mom, I had a lot more patience with my second son, but a lot less energy. When LittleDivine turns 18, I will be 58; not ancient by any means.
My mother got married at 18, had her first child at 19, her second (me) at 21. She died of cancer at the age of 53. Starting out young is no guarantee that you’ll be around to see your grandkids grow up, nor does starting late mean you won’t.
Depends how old the father’s father is. So if the grandfather died at 75, you shouldn’t have kids any later than 55.
My father became a father for the 3rd time at 50. The good news is that we’re crazy about the Littlest Bluth.
The bad news is that there is a reasonable chance that my father won’t live to see him graduate college.
My dad is 55 and having another child.
I’m 26 and my brothers are 35 and 22.
To be quite honest, I was really more worried about myself (I don’t like babies) than my dad at first, but that’s the potentially selfish older sister talking. 
In all of this, I think we are missing the bigger picture from the Original Post:
Is the world ready for a child that is half Asian, and half Troll? 
Anecdote: my father was almost 40 when I was born, Mom was 38. Older than avg, but not an extreme outlier either. Obviously, I love both parents but I would have preferred younger parents. both parents were too tired to play with me. I loved baseball, and I frankly do not remember Dad ever throwing a ball with me. And their friends were comparable ages, and they didn’t have any kids my age so I had no one to play with when they were socializing. Mom was prematurely gray and yes, she was often told what a cute grandchild I was.
My dad was 42 when I was born. He was a great dad, but we didn’t do a lot of the traditional ‘father-son’ stuff because he was just plain too old for it. Of course, he was a lot ‘older’ at 42 than I am now. Part of that is just the times we both lived in (60 is the new 40, you know), but I certainly wouldn’t be ecstatic about the idea of becoming a father again now.
Wow to both of these. I mean, I’m 53 years older than my kid, but I knew that, barring some bolt from the blue, I could keep doing active stuff with my kid through his adolescence. I love going on walks with him or kicking a ball around with him in the backyard; I’m looking forward to the day when he learns to ride his bike, so that we can go on rides together.
The day when he’s stronger and faster than me will come earlier in my life than it will for most dads (and I expect him to take great pride in it when it happens!), but if I thought there was a serious possibility that I’d have just been too tired to play with my kid a lot more often than a father in his 30s might have been, I’d have taken a pass on late fatherhood.
Of course, it helps that I’m from good stock - my grandparents were all active and vigorous into their late 70s. One grandfather was running a furniture manufacturing plant well into his 80s, and the other died of a heart attack just shy of his 83rd birthday because he was playing golf. At 7000 feet altitude. Without a golf cart. In the rain.
Of course nothing is guaranteed in life, but statistically, young parents are “cut down” extremely rarely compared to people in their late 70’s (as per the example in the OP plus teenaged children). Me, I come from a family where people age prematurely and die mostly in their 70’s. Having two small kids now at age 34, I feel quite often that I could use a bit more energy and a more supple and less achy body (mostly joint trouble). Also, it’d be really nice to be able to cope with inadequate, intermittent sleep as well as I did 10 years ago. Financially, it’s not at all certain I’ll be any better off when I’m middle aged compared to now, although I do expect and hope to be a more mellow, easy-going version of my present self by then. Still, I would never want to have small kids when I’m middle-aged, let alone older.