This actually happened with me. As I moved into my new apartment, the society was also new to me. There is an old couple (aged above 50, I guess). I asked the elderly person (after I became a bit familiar with them) how many kids he has. And he coolly replied, "Two sons, but they are not kids anymore!" Both of us laughed but this triggered a question to my mind.
His answer is valid. How many kids do you have? This means now. The answer is 'NONE' because those two sons are not kids anymore!
What should be an alternative way to express this question?
How many kids/children did you have? ~ but then this means they are dead
How many adults do you have? ~ lol!
A neutral question that works for sure...
How many sons and/or daughters you have? ~ But we generally don't ask this. How many kids/children do you have? is way more common.