Dood, F, Jasper, M
I have 10 cats, they are all related. Here is a picture of an adult male who is uncle to this 10 month old female. She is not the smallest cat we have, but pretty close, and he is the biggest cat we have. He is a very large cat, and weighs almost 20lbs, she weighs 9lbs.
Hi rara.....Yes, this is a large difference. Mind you I think your extended family of cats are naturally on the large side.
This is because the average for the domestic cat is about 10 lbs so she is near the average. That makes him very large. He is up to Maine Coon size.
And the Maine Coon is the largest breed registered with the Cat Fanciers Association.