(I suppose this node would be better titled "Why K9 wants to have children". But it's here now, so let's give it a go.)
Oh, dear. Another would-be parent who maintains that "our kids will be better than us". As a would-be parent myself, I feel compelled to issue a reality check at this point.
Point one: Your children will not necessarily be better than you.
It's just a Bad Idea to assume that your descendants will automatically absorb only the positive qualities you and your wife possess and none of the negative ones. It's an even worse idea to assume that your children will spontaneously develop only good traits without bad ones. This sort of thinking is taking natural selection too far.
Point two: Your children will not necessarily be like you at all.
Your children will be individuals. They will each be unique people with their own goals, their own ambitions, their own desires, and their own potential. They inherit certain genetic traits from each of you, but the whole of their personality is radically different from just those genes. They will not, in any way, be "more of you" or "more of your wife". Expecting your son to be a miniature clone of yourself to be improved upon is exactly the wrong way to approach parenting.
Point three: Your children might not even be "your children".
One or the other of you might be infertile and not know it. It happens. For this or for other reasons, you might decide to adopt or become foster parents instead. These will not have any of your genetic material. This does not in any way invalidate them as "your children". Be prepared for this possibility.
And now, having said all that:
I think children are great. Not everyone agrees -- I split up from a great relationship not too many years ago, in part, because I wanted to have and be around children, while she thought they were annoying little brats to be hidden away whenever possible. I'll be acquiring a stepdaughter very shortly, and I'm happy to be doing so. I hope to have my own children with my soon-to-be wife someday, but I've recognized the possibility that this may never happen.
And so, I've taken steps to prepare myself mentally. Would I like children? Yes, because I like the idea of taking the role of a father in a child's life. I like the idea that I can help one young person grow from infancy to adulthood, teaching him or her all the things I know. I don't want to mold my child into a copy of me-but-better. That's just plain unrealistic, if not impossible. But I want the chance to make a difference in one person's life, for the long term, in their youth when it counts the most.
But I also recognize the possibility that fathering children may never be an option for me. I recognize that we may adopt or foster a baby or a child or even a pre-teenager. I recognize that I may have a child who has cerebral palsy or mental retardation or some other complication that, in certain other people's eyes, makes him or her "less" of a person. I recognize that any number of disasters might happen during my life or my child's which have a permanent and lasting impact, and which I can never fix or undo or repair.
But I don't care, because I'm not interested in parenting in order to produce "Me Mark II" for the betterment of humanity. I'm not into it because I want to spread the love around -- I can show love for the people already living around me. I want to do it because that child, someday, may make a lasting impact on the world, or the country, or the city, or even his or her best friend next door.
No expectations. No presumptions. Just hope.
And that's enough for me.