The development of new communication technologies has created a wide variety of new fields in which human beings can construct identities. The past decade has seen a proliferation of opportunities to use the internet for health related advice and information and many new sites have been created where participants can construct identities, formulate problems and seek solutions concerning health related issues. This paper will report on a study of emails written in to a UK-based website concerned with health issues for young people. Our analysis was driven by corpus linguistics, a computational methodology for interrogating extensive datasets, and we have combined both quantitative and qualitative approaches to the study of language. We interrogated a 400,000 word dataset of messages and were able to identify terms whose usage was elevated compared to the English language as a whole. As well as personal pronouns, these included many terms related to sexual health and bodily development, as well as terms such as 'normal' and 'worried' which were identified for further exploration. Whereas previous research on sexual health has discovered the use of vague terms and euphemisms, here, young people described themselves, their anatomy and their identities in meticulous detail. This study enables us to define the role of health topics raised, the presentation of health concerns, and contributes towards the discovery of a distinctive 'genre' of health messages concerning sexual health which differs from that found by other researchers concentrating on face to face encounters. In conclusion we suggest that for researchers and practitioners working in health with young people in the medium of English there could be valuable lessons in communication to be learned from examination of corpora of the health care language concerned.