From the data of the 1989 Bangladesh Fertility Survey, aggregate deaths reported at ages 0-12 and 13-60 months are used to estimate infant and child mortality. Multivariate analysis shows that preceding birth interval length, followed by survival status of the immediately preceding child, are the most important factors associated with differential infant and child mortality risks; sex of the index child and mother's and father's education are also significant. Demographic factors are influential during infancy as well as childhood, but social factors, particularly mother's and father's education, now emerge as significant predictors of infant mortality risks. This indicates a change in the role of socioeconomic factors, since the earlier Bangladesh Fertility Survey in 1975.

A survey of consanguineous marriages in Japan was conducted on 1 September 1983, by questionnaires. The total number of couples surveyed was 9225. They were chosen from six widely different areas and the inbreeding coefficients from isonymy and pedigrees were estimated for each area. Random inbreeding remained constant with the marriage year whereas total (F) and non-random (Fn) inbreeding from isonymy and inbreeding from pedigrees (α) decreased with the marriage year in each area. Estimates of genetic microdifferentiation from surnames were obtained; estimates of the reduced variance indicated low microdifferentiation (0·000014-0·000081) in five areas and a higher value in Fukue City (0·0004). The ratio of FST (the average within-group a priori kinship) to α-value ranged from 0·42 in Kawanishi City to 3·9 in Minobu-Cho.

Multifactorial analyses of data from representative British and German national contraception surveys were used to examine the principal demographic determinants of contraceptive use by women. Contraceptive use appeared to be determined mainly by reference to ‘reproductive status’ (the combined impact of age, marital status, parity and future child wish). Women who were postponing pregnancies were using oral contraceptives, whereas those who wanted no more children relied more on intrauterine devices or sterilisation. Differences between the countries suggested that the choice of contraceptive method was influenced by health care policy, the organisation of the relevant services and differential provider preferences. The contraceptive method used was also related to having occasional rather than steady sexual partners (more condom use), lower educational level (less oral contraceptive use) and frequent church attendance (greater use of condoms and periodic abstinence). Contraception decisions appeared to follow a fixed pattern, based more on a couple's demographic situation (reproductive status, country, educational level and religious beliefs) than on the characteristics of the contraceptive methods. This resulted in an unnecessarily restricted choice of methods.

Psychological determinants of contraceptive use were investigated in Great Britain and Germany, using national data obtained in 1992. It was hypothesised that current contraceptive use among sexually active, fertile women aged 15-45 was related to their attitude towards the various contraceptive methods, social influences, perceptions of being able to use a method correctly and consistently, a correct estimation of fertility, and communication with their partner. Effects of age and country were also taken into account.

The attitude of respondents towards the various contraceptive methods was ambivalent and no method was seen as ideal. On medical methods (OCs, IUDs and sterilisation) many respondents expressed doubts as to their safety for health. Social influences most frequently concerned the use of OCs. Respondents considered themselves able to use oral contraceptives correctly, but expressed general fear about intrauterine devices and sterilisation, and many women believed they were not able to use condoms and periodic abstinence consistently.

Multifactorial analyses revealed that current contraceptive use was principally determined by social influences, attitude and self-efficacy with respect to medical methods. Age and country, and, for use of unreliable methods, fertility awareness also played a role. Communication with the partner was less relevant.

Contraceptive choice (and the use of non-medical methods) depended greatly on encouragement to use and being in favour of medical methods. A lack of social support for use of medical methods and a negative attitude towards them was related to higher use rates of condoms, periodic abstinence, withdrawal and reliance on ‘luck’. In the case of withdrawal and/or no method, underestimation of fertility played an additional role.

Contraceptive choice appears to be determined more by a general like or dislike of medical methods rather than on a weighing of the merits of individual available methods.

Patterns of reproduction associated with extramarital conception are examined using data on non-marital births, marital births occurring during less than 8 months after marriage, and spontaneous and induced abortions experienced by unmarried women. Trends in the incidence and demographic outcomes of conceptions resulting from extramarital coitus are analysed by means of age-specific probabilities of becoming pregnant outside marriage; and of terminating such a pregnancy by abortion, by legitimating it through marriage before confinement, or by having a baby while remaining unmarried. Substantial increases in the proportion of extramaritally conceived pregnancies leading to non-marital births are detected for the period since the late 1980s, and ascribed mainly to rising levels of unmarried cohabitation. The demographic effects of the post-1989 transition from state to market economy are discussed.

This study examines the frequency of consanguineous marriage and the coefficient of inbreeding in the United Arab Emirates (UAE). The study was conducted in Al Ain and Dubai cities between October 1994 and March 1995. A sample of 2033 married UAE females aged 15 years and over participated. The degree of consanguinity between each female and her spouse, and the degree of consanguinity between their parents were recorded. The rate of consanguinity in the present generation was high (50·5%) with a coefficient of inbreeding of 0·0222. The commonest type of consanguineous marriage was between first cousins (26·2%). Double first cousin marriages were common (3·5%) compared to other populations. The consanguinity rate in the UAE has increased from 39% to 50·5% in one generation. The level of consanguinity was higher in Al Ain (54·2%) than in Dubai (40%).

Birth interval is a major determinant of rates of fertility, and is also a measure of parental investment in a child. In this paper the length of the birth interval in a traditional African population is analysed by sex of children. Birth intervals after the birth of a boy were significantly longer than after the birth of a girl, indicating higher parental investment in boys. However, in women of high parity, this differential disappeared. Birth intervals for women with no son were shorter than for those with at least one son. All these results are compatible with an evolutionary analysis of reproductive decision-making. First born sons have particularly high reproductive success, daughters have average reproductive success and late born sons have low reproductive success. The birth interval follows a similar trend, suggesting that longer birth intervals represent higher maternal investment in children of high reproductive potential.

Family planning practices were reported by 491 married women, aged 15-49, who applied to the Family Planning Centre in Isparta, Turkey. Eighty-four percent of the women used contraception, the IUD being used most frequently. Almost half of the women married before age 18 years.