Boyfriend Agreed To Have A Baby. Is He Serious Or Not?

Been talking about kids. I have one from a previous relationship. He has none. When we talked about kids, I start having baby fever. I'm really want to have another baby, but I know he's not ready. And we have talked about it. But last night when we got home, he said that when he was working, he saw a couple with their baby and it made him think. He said that he wants to have a baby. Idk if I should take him serious or joking. What do you guys think? Please no negative comments.