If you play on PC you can download mods that let you adopt an Argonian child. (There's a Khajiit child mod as well.) This picture features Scouts-Many-Marshes who you can find at the Windhelm docks. If you do his quest and return to him wearing an Amulet of Mara, he will ask you if you're available and you can marry him. I'm not sure which other male Argonian NPC-s you can marry but I'm sure the wiki can help you in that.