I just posted a message and it got lost as my machine crashed. Oh well. Apologies if it appears again and I repeat myself.
My husband is and "oldie" parent age 55 and I am 35. He was 53 when our son was born and is by no means in need of a Zimmer frame yet! Apart from slightly less energy than me I hardly notice the age difference.
The only main disadvantage I see to him being older is that he won't be around for my son when he is in his 20s. However I feel that the first part of a person's life is more important. Many children grow up and move away from their parents and may not see them much anyway. So this is not such a big concern. Also I will be there for him and perhaps siblings too. My husband doesn't kick a football round the park but I do and so we balance his upbringing very well.
We are rather ageist in our society and tend to assume that being older is 'bad'. Apart from him not being around (and lets face it many dads aren't anyway due to families splitting up) this is the only down side. There are many positive aspects to getting older. My husband is relaxed and better informed than he was first time (he has 3 grown up kids also). This I feel will be invaluable to our son as he grows. So many young parents are still finding out about themselves. Also younger folk want to go out more and may have less money and be busy working and paying the mortgage. My husband will be retired for a large part of our son's upbringing so will actually have plenty of time for him. Again compare this to a younger dad perhaps working overtime.
Age isn't so important nowadays as people live longer and have better health. What is more important is how strong your relationship is with your spouse and with your children.
I have an uncle who is 80 who has a much younger wife and who is still doing DIY on his house. He has children ranging from age 55 to 30.
Nature intended men to continue producing sperm well into their 80s (didn't Charlie Chaplain father a child when he was around 80) so it is actually quite natural for fathers to be older parents.
My husband doesn't have any flabby bits by the way!