I did not even realize that was an issue to come BUT I don't think to be honest I am producing well anyhow. In short my ex wife and I never really tried but were not very protective against it at all and nothing ever happened. The guy she run off with it took a matter of NO TIME and she was a to be mommy. I am pretty sure I was the reason nothing was happening. I don't know that for sure but fingers kind of point that direction. So I am not even sure that is going to matter.
So now my question is since I clearly overlooked that all together just how much can it affect that part of things cause yes my to be wife has done talked about children and how much she wants one child. To be honest I have none and the thought of being a father I like far more now then I did 15 years ago. So I guess this is something I need to know more about.
I guess one big question would be is there an clear evidence that this will stop it from happening or just reduce chances of it happening?
I highly encourage you not to ignore this. I cannot tell you how big of an emotional issue this is for many women. I have seen women suicidal, depressed and downright angry when they cannot have children. Again, this is something that you need to research imo.
You cannot make assumptions about your fertility based on the above. Fertility docs and even some urologists who specialize in the subject can give you a good evaluation.
HRT will always lower male fertility as far as I know. Yes, anecdotally, some men still father children on HRT, but that is very risky, especially when your playing with your wife's future and emotional health.
This is my two cents: you need to tell all of this to your wife and show her how serious low testosterone is. (PM me and I can send you my book.) And then you need to tell her the options with pros and cons. You have traditional HRT and you are already learning some of the basics about that. But then you have a variety of fertility-preserving and even fertility-promoting strategies such as Clomid, Arimidex and HCG.
These are all a big subject in and of themselves. There is quite a bit of info on the forum, so just use the search text box above. I don't mean that I don't want you to ask questions, by the way, but I'm just letting you know that there has been some great discussions on the subject.