So I'm walking at the zoo with my son.. and some guy goes "congratulations but I know that's not yours" I looked at him and said yes he is mine

My son is mixed and people always ask me what is he mixed with.. I know the difference when people are asking because they want to know.. but this guys was saying it to be cute. It was his way of trying to hit on me.. I had a crop top shirt on and some shorts.. he looked me up-and-down before he said his comment as he walked past.. my son also looks like me