Just get on with it. Stop hanging around and do the deed. 40 is not too old for a man and in fact might encourage you to stay fit for longer. I don't remember any kids getting abuse for having older parents. Younger parents do tend to be a little smug though. For women, problems start from 30 - it becomes far more difficult to conceive and there is a greater risks involved, both to mother and child.
We started young. I'm 39, my eldest is 18 in April and youngest started secondary school in September.
We started young. I'm 39, my eldest is 18 in April and youngest started secondary school in September.

As long as you're generally fit & healthy, you have another decade to go before you have to worry about being too old, IMO.

which I feel is a little late. If one of us wasn't working it'd actually be cheaper just to have a second child now, got to love how daft the benefits system is but alas we'll wait.