Trying.

I'm pretty certain that it started with our friend Aimee's daughter Holly. We had a couple of other friends that had had kids earlier than this, but the fact that they turned out okay, and that parenthood didn't seem to be resulting catastrophic life changes for our friends could have been a fluke.
We simply didn't have enough data that indicated that kids weren't going to turn out as monsters by default.
Also, we have a pretty good life. We're financially very stable. We both have good jobs, our house is coming together nicely, we travel a lot, we're able (within reason) to pursue our hobbies as we want to.
We've never, that I'm aware of, had a sense that we were missing anything by not being parents. At least, I never did.
So, anyhow, Aimee had Holly. Holly is devastatingly cute. All our friends kids are cute (or at least they were as infants), but Holly was the first one that Kate spent any prolonged time around, and actually looks forward to seeing. That's true for other friend's kids as well now, but Holly was the first.
I remember Kate coming home from hanging out with her old pre-veterinary work buddies Aimee and Carla, and saying that if we were to have a kid like Holly that would be okay.
"But you know, there's no guarantee that any kid we produce would turn out like that."
That's me, being my usual helpful self.
She knew that, and we both figured that we wouldn't be that lucky.
But every time she'd see Holly she'd say the same thing.
I thought, this is interesting. I'm not going to get involved in this, I'll just see where it goes. I'm already on record as being willing to have kids, but being unwilling to not be married to Kate.
In any case, it didn't surprise me when, around May of '08, Kate told me that she thought we should have a kid.

That led to trying.

It's hard to get pregnant as a grown-up. We have ample evidence that it happens all the time to people that are demonstrably too young to be parents in any way except the biological. I have a friend from college that, after dating someone for years and using birth control, had unprotected sex with that person once after they broke up. As far as I know, it was the only time they ever didn't use protection. She got pregnant.
In your thirties (Kate) and forties (me), it's not nearly so easy. It involves a lot of trying.
Trying, of course, is a euphemism here for having sex. But, at least in my experience since May of 08, "trying" is way different than having sex.
I'd spent my whole sexually active life trying to avoid pregnancy.
One of the most lasting and enduring pieces of advice I ever got from my mother came when I was in college and mentioned that someone that I knew had gotten pregnant by accident.
My mother gave me a piece of maternal wisdom that I absolutely plan to pass along to this kid we're expecting (when it's appropriate, of course).
"Nobody gets pregnant by accident," Mom said. "They might get pregnant by mistake, but that's not the same thing."
Brilliant.
I've been irresponsible about a lot of things in my life (money, schoolwork, my physical well-being), but never about sex. There's no way I'm ever getting anyone pregnant by mistake.
I spent so much time trying to avoid pregnancy by mistake, it never occurred to me that pregnancy on purpose might be so difficult.
Once Kate decided that she wanted to have a kid she wanted to be pregnant right now.
Of course, it doesn't work that way.
That led to all sorts of interesting conversations and strategies that I'm not going to detail here.
I will, however, take full responsibility for any delay that occurred between deciding to have a kid, and actually achieving pregnancy.
What can I say? The ovulation stick as foreplay really really doesn't work for me.