Broadly based statistical studies into sexual behaviour are largely confined to the twentieth century. If we stretch the term sexological, however, we can find statistical studies as early as the sixteenth century.

The fruit fly Drosophila (also called the vinegar fly or pomace fly) has been used more than any other animal in sex experiments and research into various aspects of genetics.

Over a period of twelve years Masters and Johnson observed and recorded more than 10,000 male and female orgasms. Dr. Masters began his programme of sex research in 1954 after specialising for many years in gynaecology and hormone replacement therapy for postmenopausal women. He found his assistant, Mrs. Virginia Johnson - now Mrs. Masters through an advertisement. Their first subjects were prostitutes - eight female and three male - but gradually they collected non-professional volunteers: their final sample was 694 individuals.

This is "The Wolfenden Report", which dealt also with prostitution. The committee, chaired by Sir John Wolfenden, was appointed on 24 August 1954 to consider the law and practice relating to homosexual offences, the treatment of offenders by the courts, and the law and practice of prostitution.

Some research studies have been too small to appear as regular references in the literature. Kinsey himself identified on 19 studies of sex behaviour which are in any sense taxonomic. Of these the smallest were based on data gathered by a probation officer who interviewed a hundred boys who were passing through a juvenile court in Seattle, on interview returns from a hundred handicapped females, and on data derived from a study "of 40 superior single men." This latter investigation, the smallest of the nineteen cited by Kinsey, was based on single

Of all the hormones - sometimes depicted as "chemical messengers" - only a proportion are connected with evident sexual behaviour. The first hormone was discovered by Ernest Starling at University College, London, on 16 January 1902. He was investigating the origin of the pancreatic juices produced in the intestines to aid digestion. He introduced into the mucus membrane of the small intestine a few drops of hydrochloric acid, whereupon pancreatic juice started to come from the intestine. But how was the intestine stimulated to act under

There were many accounts of orgasmic response before the work of Masters and Johnson. Theirs however was without doubt the most detailed research study ever undertaken in this field. Their findings were published in 1966 in "Human Sexual Response". In particular it was concluded that the long-standing debate about the "clitoral" vs "vaginal" orgasm was largely misplaced, there being only one type of female orgasm no matter how it is caused.

The least impressive effort to study pornography in Britain was The Longford Report. In the main this report is abysmal poorly argued, uninformed by a mature grasp of human sexuality, bereft of supporting evidence, etc. We need spend no more time on it here. What is surprising is that this publication should contain a nice little appendix (Appendix V) by Maurice Yaffé as a Research Survey and Bibliography. This appendix, tucked away on pages 460 to 498, is quite out of tone with the rest of the report. In fact the conclusion undermines all Longford's

A number of the early female writers on sexual matters were mainly concerned with a specific measure, e.g. Margaret Sanger wrote on birth control. It can be argued that such a preoccupation, though praiseworthy, is not strictly sexological in nature.

The Achilles survey also deserves mention a second time as the first American study (1923) to include women in the sample surveyed. The study was carried out for the American social Hygiene Association - an organisation engaged in fighting venereal disease, with primary emphasis on suppressing prostitution.