it enjoyed a brief airing on bbc television, when it was presented by tanya byron, but is more commonly presented on radio four. it deals with issues surrounding how far measures of characteristics, both psychological and physical, can be defined as "normal". earlier series included programmes that looked at obsessive compulsive disorder, and the most recent series, as of july 2011, has looked at sexuality and immunology. the programme on immunology included review of recent research on ageing and immunology, and asked whether farmers may be more immune to certain diseases because their immune systems have had a greater chance to develop than those of the bulk of the population.