It's common knowledge that if someone in your family is diagnosed with Coeliac Disease then 1 in 10 of your close family will also have it. Remember not everyone has obvious Coeliac (bowel) issues. Many are just damn tired with eczema, thyroid problems, tooth problems and anemia. Some maybe very underweight some maybe very overweight.
Here's a useful video by a leading USA Doctor on some recent research into Coeliac Disease and gluten sensitivity and why getting tested is so vital to avoid Cancer and Heart Disease...
youtube.com/watch?v=yLJSmJ0...
Very useful for discussing with relatives who don't want to get tested for Coeliac Disease.
And for those who prefer reading here's a link to the same topic in article form instead: