<human>: Can you give me a shortened version of the text?

This came up tangentially in a heated conversation I was having via chat a couple of days ago. I registered it but in the context of conversation didn't really address it- and now I feel terrible, like I should have acknowledged it somehow: it occurred to me (later) that I should be touched that my friend is sharing this with me, and probably should have abandoned the conversational thread we were on to focus on this since it's sort of big/personal news. What should I have said during conversation, and what can I say now?

"Congratulations" seems inappropriate since there's no good news yet (and in fact these friends are not trying yet, but he told me when they will start, which is soon). "Good luck"? That also seems weird?

I also want to know this for the future, since many of my friends are recently married and many others are getting married within a year and I think this will come up soon and often. For this specific friends, I have some hesitation for responding with excitement (though I know better than to give my honest opinion of course), but for others I will be genuinely and unreservedly excited- regardless, I want to know what one should say.

Also, I have no idea what the etiquette is for the next months/years regarding this information. I don't want to seem like I don't care- and yet ANY way I imagine to address the topic seems inappropriate. Insight would be appreciated!
<bot>: My friend told me that he and his wife are trying for a baby. I want to know how I should have responded, how I can respond now, and how to respond when told this by other friends in the future.