NC for this.
Have you been asked a stupid question that has an obvious answer?
My husband and I are a white couple and have three black foster children (who we adore).
They have lived with us for many years and call us mum and dad.
When we were on holiday, there was a couple in the hotel who would always say hello when we saw them around.
On their last night the wife said "I've been wanting to ask you ... do the children realise you are not their real mum and dad"?
Rather than get upset, the kids and I just laughed about them afterwards!