Gene und Fruchtbarkeit

Wer meinen Blog regelmäßig liest, der kennt meinen Standpunkt, dass nämlich die modernen Verhütungsmethoden für das System (unsere Art) nichts anderes sind, als eine neu aufgetretene Seuche, die nun diejenigen hinwegrafft, die eine bestimmte, genetisch beeinflusste Bedürfnisstruktur aufweisen, bei welcher der Kinderwunsch nicht besonders drängend ist.

Hier nun eine Studie, die der Frage nachgeht, wie stark unser Fortpflanzungsverhalten genetisch gesteuert wird.

International Journal of AndrologyVolume 29 Issue 1 Page 46 - February 2006doi:10.1111/j.1365-2605.2005.00606.x
Volume 29 Issue 1


REVIEW
Bio-social determinants of fertility
HANS-PETER KOHLER*, JOSEPH LEE RODGERS†, WARREN B. MILLER‡, AXEL SKYTTHE§ & KAARE CHRISTENSEN¶

Summary
This paper reviews several studies that investigated the potential role of genetic factors in determining fertility outcomes. Our review demonstrates convincingly that fertility contains genetic variance; that is, differences between humans in their genetic make-up affects their fertility outcomes and fertility-related behaviours. This finding is robust using both heritabilities and coefficients of genetic variation, and using both direct measures of fertility outcomes and also fertility precursors like fecundity, marriage, fertility expectations and attempts to get pregnant (proception). Moreover, genetic variance can change over short periods of time or across educational levels, specifically for females, and the relevance of genetic variance seems to increase during times of increasing reproductive choice.The above studies demonstrate convincingly that fertility contains genetic variance; that is, differences between humans in their genetic make-up affects their fertility outcomes and fertility-related behaviours. This finding is now generalizable across molecular and behavioural genetic modelling; across measurement using both heritabilities and coefficients of genetic variation, and across both direct measures of fertility outcomes and also fertility precursors like fecundity, marriage, fertility expectations and attempts to get pregnant (proception) (Rodgers & Doughty, 2000; Rodgers et al., 2000, 2001a,b; Christensen et al., 2003). But we can make even more detailed specification than simply to assert the existence of genetic variation. Genetic variance can change over short periods of time or across educational levels, specifically for females, suggesting that social norms and human volition are contained within the explanatory system (Kohler et al., 1999, 2002; Kohler & Rodgers, 2003). In particular, during times of increasing reproductive choice, genetic influences on female fertility differentials emerge as increasingly important. Furthermore, genetic influences on fertility variance related to the onset of childbearing may be more important than those related to total family size (Rodgers et al., 2001b). In summary, therefore, this empirical work on the biodemography of fertility using Danish twins falls into the category of research encouraged by Rutter & Silberg (2000) of 'gene–environment interplay.' The specification of models in which behavioural genetic design/analysis is complemented by environmental measures is a natural way of formalizing the goals of developing consilience between biographic and demographic approaches to studying fertility. Our empirical analyses are one example of how the ultimate result of such efforts towards consilience can be greater than the sum of the parts.


http://www.blackwell-synergy.com/doi/pdf/10.1111/j.1365-2605.2005.00606.x