This article applies the statistical concepts of affinity and distance to live-birth data and suggests that the method may be of relevance in population problems. The distributions among villages in Kerala, south-west India, of the number of live births in each religious grouping are compared, and measures of affinity and distance among these distributions calculated. Such distances calculated for three successive periods show secular trends which may indicate changing patterns of group behaviour.

Family planning is not being practised in Wadi Turaba in western Saudi Arabia, which is a Bedouin community with different stages of settlement. Children are wanted in the family, and the more children, especially boys, the better the social status of the family in the community. The desire of a mother for more children does not appear to be affected by her age group, history of previous marriages or history of previous pregnancies.Knowledge about contraceptives practically does not exist, except on a small scale in the settled community. Every woman, following the Koranic teachings, weans her child exactly at the age of 2 years, which obviously leads to the spacing of births. In rather rare situations, coitus interruptus is practised.

In accordance with JBS policy, Mrs Poole was offered the opportunity of replying to Mr Bytheway, for simultaneous publication with his paper. Her comment, which has been seen by Mr Bytheway, appears below. So far as JBS is concerned, the discussion is now closed.

The object of the study was to investigate the genetic nature of personal preferences in such spheres as food, friendship, art, music, ambition, marriage and so on. The subjects chosen for the research were forty-eight pairs of identical and forty-eight pairs of non-identical twins, divided equally into males and females, with ages ranging between 17 and 40 years. Each subject, individually, was given an oral questionnaire (‘Fads and Fancies’), the answers to which were analysed statistically. The results indicate very little difference between the concordance rates of identical and non-identical twins, suggesting that the issues discussed might not be genetically influenced. One possible reason for such findings could be the unrepresentative nature of the sample.

A comparison was made between 1308 mothers delivered of twins in Aberdeen between 1950 and 1969 and mothers of singleton infants. There was a greater number of tall women amongst mothers of twins. This was more marked in primigravidae than in multiparae. The rate of twinning was less in thin women than in those who were obese or of normal build. The social class of the husband did not appear to influence the incidence of twins. The rate of weight gain in twin pregnancies, even in early pregnancy, was high compared with the rate in singleton pregnancies. The more frequent occurrence of twinning in heavier, taller women, suggests that nutrition might be responsible but this is not borne out by the findings about social class.

Pregnancy occurring in girls under the age of 17 is of particular interest to those providing obstetric care and family planning services, as well as to the social welfare services in the community. Childbirth in girls of this age carries greater risk to mother and child than in the immediately older age groups and a young mother having a baby, whether married or not, may face social and economic difficulties. This study is designed to find out basic facts about girls having terminations of pregnancy or continuing to have a baby in this young age group, relating to: parents and family of origin, housing, education, religion, knowledge of sex and fertility, use of contraception and nature of the relationship with the father of the child.

The findings suggest that there is an urgent need for improving the provision and effectiveness of sex education, that the provision of contraceptive advice to the very young should be reviewed and improved, and that the type of relationships between boys and girls leading to the pregnancies described in this study are neither casual nor ‘promiscuous’. The findings that those conceiving under the age of 15, and keeping the baby, made their first attendance at the antenatal clinic very late in the pregnancy suggests that these girls take an undue risk with their health, possibly due to the present state of the law regarding sexual intercourse in young people. The ideas of ‘wantedness’ and ‘planning’ in relation to conception are discussed.

With the increasing interest in population dynamics, research workers with differing backgrounds, such as demographers, vital statisticians and members of the medical profession, find themselves on common ground. However, this interdisciplinary contact reveals that we sometimes use technical words in different ways, depending on the terminology of our profession. When a doctor speaks about fertility, it is synonymous with the Scandinavian word frugtbarhed whereas fertilitet for the demographer only refers to live-born. Medical research within the field of fertility usually deals with conceptions, i.e. live-births, still-births, legal abortions and other hospitalized abortions, including illegal and spontaneous abortions. There are also an unknown number of conceptions, such as non-hospitalized abortions, but it is now generally believed that, in Denmark, this figure is negligible (Hoffmeyer & Norgaard, 1964; Sele & Norgaard, 1972). Moreover, during the last three decades, contraception has become more and more widespread and this new variable, which influences both births and abortions, should also be considered. Bearing this in mind it would be appropriate to refine our terminology and use ‘manifest fertility’ for conceptions and ‘potential fertility’ for all biologically possible pregnancies.

Data are presented on a representative sample of legitimate live-born first infants in England, Scotland and Wales. When they are categorized simultaneously by paternal age, maternal age and social class of the father, it is found that:

(1) Mean parental age difference (father's age — mother's age) is higher in upper class births than in other births.

(2) If a man is younger than his wife, he is probably more likely than otherwise to come from the lower social classes, though this conclusion becomes less secure as the age difference increases in this direction.

(3) Mean parental age difference increases with paternal age and decreases with maternal age.

(4) For a given paternal age, parental age difference increases with a decline in social class, and for a given maternal age, parental age difference increases with a rise in social class.

(5) In general, young parents have smaller mean parental age differences than old parents.

If such mating patterns are characteristic of white North Americans one would infer:

(1) that the risks of neonatal death and stillbirth previously reported in association with aged paternity are the result of biological rather than sociological phenomena, and

(2) that the risks of neonatal death and stillbirth previously reported in association with youthful paternity are the result of sociological rather than biological phenomena.

In general, it seems that mean parental age difference is unlikely to be a fruitful clue to the aetiologies of pathological conditions unless there are simultaneous controls on the age of at least one parent and on social class.

The question is raised whether age disparity between spouses is associated with childlessness as well as with perinatal death and congenital malformations.

The results of a comprehensive daily fertility clinic are presented for the years 1970–72, together with a 2-month schedule of investigation for the couples. Twenty-seven per cent had ovulation problems, 18% fallopian tube blockage or adhesions, 25% oligo- or aspermia and 27% were normal to investigation. The treatment of these conditions is discussed; the highest pregnancy rate was seen in those with no treatment (45%) indicating the use of reassurance after complete investigation.

Twenty-eight South African Negro albinos have been tested for intellectual maturity and body image boundary, characteristics and a comparison made with carefully matched normally pigmented controls. The albinos were found to be more intellectually mature than the controls but the control group showed slightly more diffuse body image boundary differentiation than the albino group.

The 1935 Criminal Law Amendment Act translated the Catholic Church's doctrine regarding contraception into the law of the land prohibiting the sale, importation and advertising of ‘unnatural methods’ of contraception.

Over the years, public opinion has changed and it has been estimated that over 20,000 Irish wives are taking the pill in spite of Humanae Vitae. Family planning clinics have been set up in Dublin.

In 1973, the Supreme Court ruled in the McGee case that the ban on importation was unconstitutional and violated private rights.

Three private member's bills have been defeated and a Government bill to amend the 1935 Act is before the present session of the Dáil. It is a conservative measure seeking to restrict the importation and selling of contraceptives to licensed persons and making it an offence for unmarried persons to purchase them. It is probable that the bill will be defeated by Government members who regard it as too permissive and that the law will be further liberalized by more test-cases in the Courts.

The number of Northern Ireland women obtaining abortions in England has risen sharply from 36 for April–December 1968 to 775 in 1972. The figure for 1973 when it becomes available will probably be about 1000.

The sample on which this paper is based consisted of 522 women who between January 1971 and August 1973 sought an abortion through the Ulster Pregnancy Advisory Association. The sample amounted to about one-quarter of all residents of Northern Ireland obtaining an abortion in England over the same period and was therefore not a random one. It was, however, fully representative for age and marital status and was thought to be generally reliable.

The 522 women included 108 Roman Catholics, who were therefore under-represented in the sample compared with the general population at risk.

The 108 Roman Catholics included 72.2% of single women, compared with 65.1% of single Protestants; they were also younger, 42.6% coming with the age group 20–24 years compared with 33.4% of the Protestants, and a higher proportion, 46.3% compared with 30.9%, had stayed at school to the age of 17 or 18 years. Only 15.7% of the Catholics had been told of the UPAA by their own doctors, compared with 45.7% of the Protestants.