Semen and serum vitamin B12 levels in Indian lactovegetarian and non-vegetarian subjects were estimated along with routine semen examination. Lactovegetarians had distinctly lower serum and semen vitamin B12 levels than the non-vegetarians. However, in normal and oligospermic subjects the ratio of semen vitamin B12 to serum vitamin B12 in the various diet groups was not significantly different and was always greater than one. In azoospermic subjects the serum vitamin B12 levels were always higher than the corresponding semen vitamin B12 values. Although semen vitamin B12 content was related to serum vitamin B12 level and sperm concentration in the normal and oligospermic groups. Further, in healthy lactovegetarians with low serum and semen vitamin B12 content and oligospermia, treatment with hydroxocobalamin produced no significant improvement in semen quality.

Estimates of the incidence of illegally induced abortions are critically reviewed and on the basis of a revised estimate it is tentatively suggested that there were 50,000 (legal plus illegal) abortions induced annually between 1964 and 1966. A substantial reduction in the extent of illegal abortions is an important consequence of the 1967 Abortion Act. But induced abortion is seen as a contributory factor only in the decline of legitimate fertility which has been greater at all ages and all parities than the increment of abortions to married women. A particularly marked reduction in legitimate births occurred between 1972 and 1975 whereas the number of induced abortions performed on married women declined slightly. However, the reversal of the secular trend of increasing illegitimacy is evidence of the demographic impact of the Act. Regional rates of abortion are found to be unassociated with the decline in high parity births but nagatively associated with illegitimacy ratios. At the regional level differences in the proportion of abortions performed under the NHS remain. At the national level a lower proportion of early terminations occur in the public sector than in the private sector, and women in the least skilled occupational groups have their abortions latest.

Interviews were carried out with 979 women attending a clinic for birth control advice. Most of the patients were single, middle-class women who worked in central London offices. More than 600 had never approached their GP for advice; of these, about 200 were reluctant to do so because of embarrassment or fear of the reception they might get. Those that did visit a GP intially tended to complain of a lack of interest. Fewer patients who had sought help from a local family planning clinic expressed a similar dissatisfaction but one-third did criticize the facilities and service provided. Two-thirds of the patients were surprisingly ignorant about the contraceptive facilities available in the areas in which they lived.

The agreement between zygosity diagnosis in twins by reference to the twins' own answers to written questions and diagnosis based on an objective assessment of zygosity by blood-typing is studied for 178 pairs of same sex twins. Seventy-two female and 106 male twin pairs answered two questions concerning their similarity in appearance and frequency of confusion in childhood, and were blood-grouped using up to 23 different antisera. Of those pairs concordant for all markers and diagnosed as MZ, 98% agreed that they were confused in childhood and that they are alike in physical appearance. Only 55% of those pairs discordant for at least one marker and classified as DZ agreed that they were never confused and are not alike in appearance. The replies of the remaining 45% are spread over all the other combinations of responses. If all twins who agree that they were confused in childhood and are alike in appearance were to be classified as MZ on the basis of the questionnaire alone, and all others as DZ, the diagnoses of only seven pairs out of the total 178 (3–9%) would disagree with those based on blood group data.

A group of 20 brain-damaged (BD) subjects was added to the canonical analysis, reported earlier, of mandibular symphysis shape, in the following groups: (1) Down's syndrome (DS), (2) familial idiopathic sub-normality (FIS), (3) intermediate intelligence (II), and (4) high intelligence (HI). Significant separations between means were found for all pairs of groups, except only II–HI. The separation between the BD and FIS groups supports the hypothesis that a genetic mechanism (pleiotropy) underlies the link between intelligence and symphysis shape, but environmental influences probably account for most of the separation between the BD and the two normal groups. The findings have implications for the study of behaviour genetics

The Griqua, a people of mixed ancestry living mainly in the northern part of the Cape Province, South Africa, bear surnames of British, non-British North Western European, Khoisan, Sotho/Tswana and other Negro origin, as well as a number indicating probable descent from slaves. Bearing in mind the historical circumstances of the formation of the Griqua nation and the relative importance of pater and genitor in the social system, it is possible so to analyse these surnames as to derive a quantitative estimate of the varieties of admixture in the people. The results accord closely with, and amplify, those of a sero-genetic study, which in turn furnishes explanations for some points not amenable to isonymic analysis. The combination of both types of investigation has both provided mutual corroboration and enabled more information to be extracted than would have been possible from either type of investigation on its own.

Sixty-seven GPs from a suburb of Copenhagen were interviewed regarding their experience with and opinion of induced abortion. The younger physicians in the sample were (a) significantly more experienced in areas of medical practice relating to abortion care, (b) significantly more positive in their attitude towards abortion, and (c) significantly more likely to emphasize the provision of contraceptive services to women undergoing pregnancy termination. Independent of the influence of age, a significant positive correlation was found between abortion attitude and the emphasis placed on providing contraception. A physician's self-perceived success in providing post-abortion contraception was found to relate in part to his/her view of the proper role to be played by a GP in abortion cases.

Contraceptive knowledge and behaviour of mothers of large (five of more children) and small (under three children) families in four subcu;tures were compared with white Protestants. Four hundred and forty-nine mothers aged 35–45 years were studied from black, Cuban, Indian, Chicano, and white groups. With social class, knowledge of birth control, and degree of religiosity held constant, the best predictors of family size were the mother's desited family size (expressed as desired minus actual children) age at childbirth, and age at mariage. Data suggest that family size is not purely a function of birth control knoeledge but related to early marrage and pregnancy and in keeping with attitudes about an ideal family size. In general, factors related to size were stronger in the white group than in the subcultures, and in a few instances certain cultures were not consostent with others in overall trends.