Having children for a variety of reasons can be 'morally' wrong, or even 'fundamentally' wrong, but I've never considered the age of the parents to be an issue per se, whether it's the female or the male. Although I do crib at women who artificially prolong their ability to bear a child well past the natural child-bearing age, in order to satisfy their own maternal urges. That smacks more of vanity to me, wrong as I may be.
It's perfectly fine in many societies for teenage girls to be married to men who are three times their age, and who may already have a wife or wives, and children considerably older than their new bride. Provided the male's able to give his wife/wives an equal standard of living and status, no shame is attached to that, and, far from the begetting of more children being shameful, they are considered a blessing to the family. Of course, this pretty picture doesn't always work out, but then neither does Love's Young Dream!
Another thing nowadays is that people are living longer and, if actuarial tables are to be believed, living better and healthier lives. A man of 50 today stands a better chance of being in good body and mind in 20 years' time. It's also a matter of mental attitude towards kids - if you like them and enjoy them, you presumably want to have them?
Like Maurice - I don't doubt he'd be a cracking Dad to a new babe, and even if he snuffed it at 75 - so what? His kid's grown up by then, and will have known he/she was wanted and loved - about 100% more than thousands of absentee 'fathers' in their 20s will have ever offered their various and assorted produce. It's all too individualized, personal, and wide-ranging to be tied to one assumption or another, in my humble, and childless, opinion!