(How) Do you communicate this consideration with people that made children recently?
I have the same feeling but humans have a strong paternal/maternal instinct (which is great), conversation suffers as a result.
In public the only place I have communicated this consideration is right here. Privately I have communicated this consideration with family and close friends. One of these friends has started actively trying to make babies with his girlfriend after we first started discussing this topic. We have discussed it after he started trying. We have a friendly discussion about it, then move on to another topic. I find conversation does not suffer at all. That is, with the people I have carefully chosen to discuss this with. I can imagine conversation would suffer with most people I would strike up a conversation with in let's say a supermarket.