ale ...
Popieram ustawę o związkach partnerskich. Wspólne dorabianie się majatku i dziedziczenie jest OK. Jedyną kontrowersyjną sprawę widzę w adoptowaniu chłopców przez homoseksualne pary męskie pary gdzyż w poważnym badaniu Szwedom wyszło, że meski homoseksulizm może być (przynajmnej u 17%) nie wrodzony lecz wynikiem wpływów społecznych w okresie dorastania.
Sposród wszystkich w całej Szwecji (!) jednojajowych bliźniaków do lat 47 5% trafiło do homoseksualizmu. Były to 72 pary, w których co najmniej jeden był. Aż w 64 z tych par bliźniak trafił do tej orientacji sam - bez brata. Dlatego badacze zdecydowali się napisać nawet w abstrakcie że czynniki społeczne ("social") też mogą decydować o trafieniu lub nie do tej orientacji. Nie znaczy to że nie rodzą się chłopcy zdecydownie niepodatni na wpływy społeczne i od razu niezachwianie już z taką orientacja, tylko że nie wszyscy są tacy. Są też nie tak zdecydowanie ukształtowani. Ponadto napisano że znane są społeczności które osiągneły 20% co też było argumentem, że co najmniej 15% (20%-5%) noworodków męskich może nie mieć zdecydowanie wrodzonej orientacji.
link.sprin(*)le/10.1007/s10508-008-9386-1Najistotniejsze fragmenty:
Genetic and Environmental Effects on Same-sex Sexual Behavior:
A Population Study of Twins in Sweden
Niklas La°ngstro¨m A Qazi Rahman A Eva Carlstro¨m A
Paul Lichtenstein
Received: 8 October 2007 / Revised: 29 February 2008 / Accepted: 19 April 2008 / Published online: 7 June 2008 Springer Science+Business Media, LLC 2008
Abstract
There is still uncertainty about the relative
importance of genes and environments on human sexual orientation.
One reason is that previous studies employed selfselected,
opportunistic, or small population-based samples.
We used data from a truly population-based 2005-2006 survey
of all adult twins (20-47 years) in Sweden to conduct the
largest twin study of same-sex sexual behavior attempted so
far. We performed biometric modeling with data on any and
total number of lifetime same-sex sexual partners, respectively.
The analyses were conducted separately by sex. Twin
resemblancewas moderate for the 3,826 studied monozygotic
and dizygotic same-sex twin pairs. Biometric modeling
revealed that, in men, genetic effects explained .34-.39 of the
variance, the shared environment .00, and the individualspecific
environment .61-.66 of the variance. Corresponding
estimates among women were .18-.19 for genetic factors,
.16-.17 for shared environmental, and 64-.66 for unique
environmental factors. Although wide confidence intervals
suggest cautious interpretation, the results are consistent with
moderate, primarily genetic, familial effects, and moderate to
large effects of the nonshared environment (social and biological)
on same-sex sexual behavior.
Introduction
The prevalence of same-sex (or homosexual) sexual behavior
varies over time and geographical region; population-based
surveys suggest lifetime estimates of 3-20% for men and 2-
9% in women (Caceres, Konda, Pecheny, Chatterjee, & Lyerla,
2006; Sell, Wells, & Wypij, 1995). The origin of samesex
sexual behavior is of obvious interest to theories regarding
the development of sexual preferences (Rahman, 2005).
However, the issue is also important for professionals concerned
with sexual health in general and the psychological
health of non-heterosexual populations. Same-sex behavior
remains a substantial correlate of sexually transmitted infections
in men and is also associated with increased risk of
physical and psychiatric morbidity among both men and
women in the general population (Cochran & Mays, 2000;
Sandfort,Bakker, Schellevis,&Vanwesenbeeck, 2006; Sandfort,
de Graaf, Bijl, & Schnabel, 2001).
...
Results
Fewer men (407/7,231; 5.6%) than women (835/10,676;
7.8%) reported any lifetime same-sex sexual partner, v2(1) =
32.11, p\.001. The average number of same-sex sexual
partners among those reporting any such partner was 12.86 in
men and 3.53 in women, Wilcoxon rank sum test = 8.75,
p\.001. A weak negative correlation between any lifetime
same-sex partner and age was found in women, rho = -.05,
p\.001, but not in men, rho = .01, p = .24.
Table 1 shows twin resemblance and estimates of genetic
and environmental influences on same-sex behavior for both
men and women. Twin resemblance for the two measures
was moderate overall, but higher upon direct comparison in
monozygotic than in dizygotic twins for both sexes
(Table 1). In men, the full twin model suggested heritability
estimates of 39% for any lifetime same-sex partner (95% CI:
00-59%) and 34% for total number of same-sex partners
(95% CI: 00-53%) whereas unique environmental factors
accounted for 61% (95% CI: 41-85%) and 66% (95% CI:
47-87%), respectively (Table 1). No shared environmental
effects were found among men. For women, 18-19% of
...
Discussion
...
In conclusion, although confidence intervals were wide,
we believe this study provides the most unbiased estimates
presented so far of genetic and non-genetic contributions to
same-sex sexual behavior. The results should inform further
research on this complex trait.