I mean, it's not really that I have a good reason to not want one, I just... Don't. I'm 32, if she got pregnant today I'd be 33 when she had it, which means I'd be 51 when it's 18. That's pretty damn old to be trying to keep up with a teenager.
I also don't want to go through the bullshit that newborns/babies bring, which I admit is pretty selfish. We do pretty well financially, but holy shit does it take a lot of money to keep a baby supplied with it's needs...
I brought up adopting a slightly older child, but "it's not the same". I explained that it would be good for her, great for the kid getting a stable home, etc, but it's a no go.
*Sigh*
Anyone who would say "it's not the same" is not in the right headspace to raise any child, biological or adopted. Set your foot down about what you want and how this will affect the whole family.