@Pauline750
Yes, I have found this too. I don't have the problem anymore because I only host long term guests and solo travellers but, when I did host short term stays, I often got guests wanting to bring children. It does say quite clearly in my listing 'no children' and not just in the house rules but Airbnb has a tendency to bury the important information.
Like you, I found that some people got very angry. Usually, they would try to convince me to make an exception for their child, who was by all accounts an absolute angel. Some would get irate when I continued to say no. It's like they feel you have made some sort of personal insult to their child. One lady told me I must be a terrible person if I didn't like children. I never said I didn't like kids, just that my listing was not suitable for them.
Another lady tried to get devious about it. When I explained the reason she couldn't instant book my listing was because she had entered 1 x adult and 1 x child, she changed the booking to 2 x adults. It didn't matter that I had told her I didn't accept children nor that she was actually bringing two kids and my listing had a maximum occupancy of 2 guests. When I explained that my other guests have booked on the assumption that there would be no children, she said they won't notice because the kids are tall!! Honestly, some people really can't take no for an answer.
Eventually, I had to change the wording to:
I do not host under 18s UNDER ANY CIRCUMSTANCES.
I feel like that did the trick, because I don't remember getting more requests like that afterwards.