Cousins are funny things. As a child they were the kids you played with when your parents dragged you out on Sundays to visit relatives. As you got older you probably saw them less and less until one day you realised you couldn't remember what they looked like.

At family funerals over the past few years I have become re-acquainted with a host of cousins I hadn't seen for a lifetime. Some had changed dramatically, afro perms and black pencil moustaches had given way to receding gray hair and lined faces. The curious thing though was how alike we all were. As we aged our inherited characteristics had emerged. The commonality of our genes had become far more evident than it ever seemed in childhood.

Looking around a family gathering I was reassured by the fact that so many people looked like me and shared similar personalities. I was though struck by the realisation that my own children would never have the same experience of having so many close relations. The small size of modern families reduces the number of potential cousins today's children have. I have around 100 first cousins, my children are unlikely to have more than ten. Is this a by-product of progress and prosperity we should celebrate or be concerned by?