This year, the French are commemorating the centenary of the death of their distinguished countryman Louis Pasteur, chemist and bacteriologist. Yet few people in France or elsewhere will be aware of a fact which I recently discovered: Louis Pasteur and the Czech geneticist Gregor Mendel were born in the same year - 1822. That Pasteur and Mendel are exact contemporaries is a most significant coincidence, for their respective careers symbolize the parallel and contiguous development of medical and genetic knowledge in the nineteenth century. This in turn paved the way for man to discuss, investigate, increase and spread understanding of human reproduction, disease and life-span, and to utilize scientific understanding of these subjects to increase the well-being of mankind in the twentieth century. Indeed, the human relevance of these biomedical discoveries caused them to eclipse those of other branches of knowledge in this century.

Large twin samples and recent applications of multiple regression techniques to behavioral genetics methodology makes possible evaluation of genetic and environmental contributions to the articulation proficiency of individual phonemes. Factor analysis of the articulation scores from 256 MZ and DZ twins and 124 of their non-twin siblings (all children ranged from 2; 11 to 9; 8 years) were conducted to reduce a 50-item articulation test to a more manageable set of five articulation factors. The twins' factor scores were then analyzed using multiple regression procedures to determine the extent to which the individual factors resulted from genetic and/or environmental influences. The /r/ and /∫, t∫, dƺ/ factors were found to have strong genetic components, while the /l, j, w/ factor was found to be strongly influenced by environmental sources of variation.

The are two common replies to the question of whether carriers of genetic disorder should have children. The first simply ends any argument by claiming that everyone has an inalienable right to have children. In many ways this view is quite attractive. The right is said to be universal as well as inalienable. It avoids odious comparisons and applies to everyone, including those whom society has deemed unfit for the flimsiest reasons.

In the United Kingdom, for example, a High Court judge recently upheld the decision by Sheffield Health Authority to refuse IVF treatment to Julie Seale, who was then 36, on the grounds of her advanced age. This latest salvo in what one writer has called “the fertility war” follows on from the Grand Peninsular Campaign against IVF treatment for post-menopausal women and the recurrent guerilla battle over enforced sterilisation. As this author remarks, “What has happened without our really noticing it is that, with every new skirmish in the fertility war, we are becoming more and more comfortable with the idea that some people deserve to be parents more than others” [1]. And in an age of what is essentially payment by results, there is a great temptation for healthcare providers to think that those who deserve to be parents are those with the best clinical chances.

This study investigated the degree of risk of handicap in twins, triplets, quadruplets and quintuplets and associated factors, and examined the clustering tendency of handicaps. The sample was recruited from the Kinki University Twin and Higher Order Multiple Birth Registry. This panel consisted of 705 pairs of twins (1410 twins), 96 sets of triplets (287 triplets excluding 1 infant death), 7 sets of quadruplets (27 quadruplets excluding 1 infant death), and 2 sets of quintuplets (10 quintuplets), all of whom were born after 1977. The incidence of handicap was 3.7% in twins, 8.7% in triplets, 11.1% in quadruplets, and 10.0% in quintuplets. The risk of prodicing at least 1 handicapped child was approximately 1 in 13 pairs of twins (7.4%), 1 in 4 or 5 sets of triplets (21.6%), and 1 in 2 sets of quadruplet and quintuplets (50%). There was a significantly higher clustering tendency of handicaps in twins and triplets compared with the expected frequency calculated from the incidence rate of handicap. Four significant risk factors for subsequent handicap were found by logistic regression: gestation number, shortening of gestational age, premature rupture of the membrane, and toxemia during pregnancy.

The objective of this study was to evaluate the association between maternal factors, including rates of gestational weight gain before and after 24 weeks' gestation, and adequacy of intrauterine growth for gestational age at birth of triplets, as a mean Z-score of the triplet set. The study design was a retrospective, anonymous, pilot telephone survey of mothers of triplets and an historical cohort analysis of their prenatal weight gain records. The statistical analyses performed included multiple regression analysis to formulate a model for mean triplet Z-score (a measure of birthweight-for-gestational age) and analysis of variance to confirm and simplify the components of this model. Factors significant in the final model and their beta coefficients included weeks' gestation (-0.124, p <0.0001), rate of gain before 24 weeks' gestation (0.606, p = 0.005), and induced conception (−0.404, p = 0.01). Rate of gain > 1.5 lbs/week before 24 weeks was significant in the analysis of variance (p = 0.009). Better intrauterine growth for gestational age is achieved in triplet gestations with maternal weight gains of >1.5 lbs/week before 24 weeks' gestation.

The retardation of fetal growth in twin as compared to singleton gestations may be due to maternal and/or placental factors. The separate birthweights and related placental weights of 487 dichorial twin pairs were recorded, and the heavier placental weights of firstborns in comparison with second-borns were found to be related to the heavier birthweights of firstborns compared to second-borns. The lighter placental weights of firstborns compared to second-borns were found to be related to the lighter birthweights of firstborns compared to second-borns. Obviously, the placenta itself may may very well be the cause of the retardation of fetal growth in twin gestations.

This study considers the replies to a 14-item questionnaire, by 27 monozytogic (MZ) and 38 dizygotic (DZ) pairs. Another sample consisting of 48 sets of parents of twins (24 of whom were MZ and 24 DZ, not necessarily corresponding to the couples of twins actually studied) was used, to answer a questionnaire directly related the one put to the twin pairs. The results of statistical tests performed (canonical correlation and Fisher's discriminant) indicate that only in MZ twins does self-awareness outweigh pair-awareness. This does not seem to be related to any difference between MZ and DZ twins in the education/upbringing received from their parents.

The object of this study was to develop a theory of the relationship between a mother and her unborn twins using a qualitative grounded theory methodology. Ten women participated in interviews during the last trimester of a twin pregnancy and again during the early postpartum period. Data provided by these women was analysed using the constant comparative method. Two additional informants were sampled in order to formulate and verify the tentative theory. For women in this study, the findings indicate that mothers form a relationship with their unborn twins within the wider context of accommodating the twin pregnancy in their lives. A woman accomplishes this process by immediately seeking information about twin pregnancy, by making room, in all senses, for two babies instead of one in her life, and by appraising her own pregnancy risk. A mother engages in self-protective behaviors and in behaviors designed to protect the health of her unborn twins as a method of coping with the perceived risk of the twin pregnancy and with the twin pregnancy itself. As the twin pregnancy progresses, women move toward accepting the idea of being pregnant with twins. For women pregnant with twins, the birth of two infants confirms the reality of the pregnancy.

The usefulness of PCR systems (D1S80, D17S30, ApoB, TC11, VWA, and SE33) is discussed. The statistical evaluation shows that these systems – together with other systems – are well suited for zygosity testing.