Demographic Behaviour and Behaviour Genetics
Vetta Atam, Courgeau Daniel
The use of behaviour genetic heritability analysis to study demographic behaviour is fraught with problems. We explain the concepts and methods used by behaviour geneticists, which are based on Fisher (1918) and Jinks and Fulker (1970), point out their deficiencies, and show that the basic assumptions of the behaviour genetic model do not hold. A behavioural trait should be analysed not by using heritability but by using the coefficient of intensity of inheritance. Confusion between statistical concepts and heritability abounds. Fertility differs from other behavioural traits in many respects. It is affected by many known environmental factors. Male and female fertility are affected by different factors and should be studied using different techniques. Galton’s 19th century idea of nature-nurture or Fisher’s early 20th century genetics have little use in the genomic era. We need new concepts. One of these could be the species value of a gene, another is regulatory genes i.e. + or - genes that regulate a behavioural trait. The latter poses a serious challenge to the Fisherian concept of additive genes and this concept has to be discarded. Molecular genetics is the key to the understanding of human and animal behaviour.
Censuses, Elections and Population: the Case of Macedonia
Courbage Youssef
Despite the small size of the population, the question of numbers is important in Macedonia. Censuses were carried out in 1994 and in 2002, the results from the former having been disputed, notably by the main minority, the Albanians. In this article, the quality of the 1994 Census results is tested against several other sources. First, the structures by ethnic group, age and sex from the 1971 Census, held during the Yugoslav period, are projected to 1994 using the cohort components method and compared with those obtained in the 1994 Census. The detailed results of the 2002 elections are then used to estimate the composition of the electorate (population aged 18 and over) under various hypotheses regarding the electoral turnout rates of different ethnic groups and the transfer of votes from the small minorities (Turks, Roma, Bosnians, etc.) to the Albanian or Macedonian parties. These two simulations, effected on the total population (resident in Macedonia or abroad), show the 1994 Census results to be on the whole satisfactory. In addition, natural increase (births minus deaths) between 1994 and 2002 is used to estimate the population of Macedonia by ethnic groups in 2002, before publication of the results from the 2002 Census. Finally, the growth projections for the ethnic groups are examined in the light of fertility differences and the proportion of young people in the age structures of the various populations.
Re-Emerging Diversity: Rapid Fertility Changes in Central and Eastern Europe After the Collapse of the Communist Regimes
Sobotka Tomás
This article provides a detailed analysis of recent fertility changes in 15 countries of central and eastern Europe and in the former East Germany. It focuses on the period after 1989, which witnessed a profound transformation in childbearing patterns, including a rapid decline in fertility rates, the postponement of childbearing, and an upsurge in the proportion of extramarital births. These shifts went hand in hand with changes in union formation, abortion and contraceptive prevalence. While the intensive decline of the total fertility rates seems to indicate a uniform reaction of former Communist societies to the ongoing social and economic changes, the analysis reveals that there was increasing diversity in fertility patterns across the region. The article pays particular attention to the interplay between postponement of childbearing and period fertility levels. The progression of the postponement-indicated by an increase in the mean age of women at first birth-has varied widely between countries. We hypothesize that the more rapid postponement of parenthood was related to the success of the transition period, and to the extent it brought new opportunities and choices for young people and shifted the institutional structure of many societies considerably closer to the structure of western European countries.
Men Medically Assisted to Reproduce: AID, IVF, and ICSI, an Assessment of the Revolution in the Medical Treatment of Male Factor Infertility
La Rochebrochard Élise de.
In response to involuntary infertility, which affects 15% to 20% of couples, the techniques of in vitro fertilization (IVF) have been developed. Between 1982 and 2000, 85,000 children were born in France thanks to IVF (estimates based on combined analysis of the FIVNAT survey and administrative data). Five world reports and two European reports have been produced on IVF, but their use remains limited by incomplete data for regions such as southern and eastern Europe. The success rates with IVF are around 15% to 20% of pregnancies obtained per retrieval. However, these rates decline rapidly as the woman’s age rises and when the man’s sperm has severe abnormalities. In cases of severe male factor infertility, artificial insemination by donor (AID) was for long the only medical solution, but it raises the problem of accepting sperm from a donor. Since 1992, a new IVF technique, intracytoplasmic sperm injection (ICSI) is available. This technique has been widely adopted in France and in many other countries: in 1998 it represented 30% to 60% of assisted fertilizations. Despite this large development, numerous questions remain concerning the consequences of the technique, particularly regarding the short- and long-term health of children conceived by ICSI.
Recent Demographic Developments in France
Prioux France
Natural increase in France remains one of the highest in the European Union, since the age structure of the population remains relatively favourable to births over deaths. Estimated net migration in France is relatively low compared with that in neighbouring countries, though the number of residence permits issued to aliens has increased considerably in recent years.After a strong increase in 2000, the total fertility rate was unchanged in 2001 and 2002 (1.89 and 1.88 births per woman). The upturn between 1995 and 2001 is largely due to first births. The recovery of fertility at younger ages was not confirmed in 2002 and women aged 30 and over contributed most to fertility. However, completed cohort fertility declined rapidly after the 1960 cohort.
After increasing strongly in 2000, marriages declined slightly in 2001 and 2002; in a growing number of cases, at least one of the partners is a foreign national. The popularity of the Civil Solidarity Pact (PACS) is still increasing rapidly from one cohort to the next, while the frequency of divorces is settling at around 38 divorces per 100 marriages.
Female life expectancy at birth (82.9 years in 2002) is increasing less rapidly than that of men (75.6 years) and the resulting trend to convergence can be expected to continue since excess male mortality, which is very high in France between ages 15 to 65, is declining slightly.
Age at First Union in France: A Two-Stage Process of Change
Prioux France
The "Study of Family History" Survey concurrent with the 1999 French census has for the first time made it possible to measure the proportions and ages of men and women forming first unions, and to observe the annual changes in first union formation.
The age at first union fell between approximately the 1930 and 1955 cohorts, in particular among men. The timing of first union has been substantially delayed. Over roughly fifteen cohorts, the median age has increased by more than two years for men and women, and this trend toward later first unions seems not to be complete.
Period indicators of union formation are calculated for the years 1960-1998 and used to date the reversal of trend to the mid-1970s and to link the annual variation of these indicators to levels of youth unemployment. The lengthening of education has had a fairly consistent delaying effect on union formation, but unemployment levels appear to have initiated the movement and modified its pace.
The postponement of first unions is accompanied, particularly among men, by an increase in the proportion of individuals reaching age 50 without ever having lived in a stable union. Several possible explanations are advanced for this: the rising frequency of non-cohabiting partnerships, the greater instability of unions, and the increasing difficulty, for some men, of finding a partner for life.
