Serial Offenders

I have some colleagues who first ping me that they want to talk about work. But when they call, they pounce on me with, "How are you, how are the children?" It's so annoying, puts me off instantly. I take a deep breath, tell them the children are fine and then I'm forced to reciprocate by asking about their children. The thing is, it doesn't matter; they'll talk about their children anyway. I have to wait for the next immediate pause to steer the conversation to what should've been, the work. I wish I could tell them that if they want to talk about the children in the workplace, they've got the wrong person. They can't take it for granted just because I'm a mother.