Not to promote controversy, but I have done several research papers
related
to this topic in my life. I'm not sure what the current consensus is
but at
the time it seemed there was both a genetic aspect and a developmental
aspect, at least in human men. Sibling number, parent age, etc. was
tied to
likelihood of homosexuality. I also know that people have documented
various kinds of sexuality in animals as basal as dragonflies and as
complex as us. I'm also not entirely remembering the statistics off
the top
of my head, but something like 20% of men have admitted to
homosexual acts
but only 3% (?) state they are homosexual. So, this huge variation and
pervasiveness in multiple species seems to indicate either the
genetic/biological basis is there and there is much more of a bell
curve on
sexuality than just heterosexual or homosexual.
My best assumption that I'm sure smart folks than me are working on, is
that sexuality has a pretty wide band and is related highly to
community
and culture in primates. Humans may be the only species that can
actively
'decide' to live their life as either gay or straight, whereas most
species
are doing what either feels good or what their 'culture' dictates.
If our
basal state was some kind of bisexual, rather than heterosexual,
because
many of the other species exhibit this, I think that would make a
compelling case for why these behaviors and the biological basis
persist.
Furthermore, I imagine the trait (if there is one) of 100% homosexual
individuals persists because of factors like cultures where this is a
dangerous state to be. Homosexual men can certainly have sex with
women and
father children and are probably apt to do so in societies where such
things are mandated.
Also, from a historical perspective many human cultures were much more
accepting and opening about varying sexuality and family types. I'm
sure
anyone who took a European history learned about this in the chapter
on the
ancient Greeks.
My two cents. But I encourage anyone interested to look it up. There
are
some great scientific papers and psychological studies about sexuality
floating around and probably many more as our attitudes in this country
change.
On Thu, Mar 28, 2013 at 10:42 AM, Martin Meiss <[email protected]>
wrote:
Here are what I see as some problems with the idea that
homosexuality in
humans is rooted in the genetics of kin selection, as proposed
earlier in
this thread.
1. Suppose an individual is born with a mutation that makes him/her
inclined to homosexuality and to avoid reproduction. If this
individual
then "helps around the nest" he/she may enhance the survival of near
relatives WHO DO NOT BEAR THE GENE, since the mutation is new. How
would
this mutation enter the population?
2. Insofar as the kin-selection mechanism requires restricted gene
flow,
how can we assume that this condition prevailed for our wondering,
hunter-gatherer ancestors? Wondering groups don't have to be in
contact
very long to exchange mates or rape each other.
3. It's not clear that an individual's personal inclination to
engage in
mating behavior would have much to do with whether they actually
mated.
I
refer, of course, to rape, but also other forms of social persuasion.
Also, just because a few males in the group may prefer each other to
females, that doesn't mean the remaining males couldn't keep all the
females pregnant, thus favoring their genes over the non-players.
4. The hypothesis, as presented in this thread, seems to rely on early
populations having been resource-limited, so they would benefit from
decreasing the number of mouths to feed. But isn't it also
possible that
they were NOT resource limited. If migratory groups were expanding
into
new territory, they might have faced abundance of resources,
especially
as
their tools and weapons made more things available to them. Also,
given
the defenselessness of naked humans or pre-humans when unarmed, and
the
dangers of hunting nasty animals when armed, it is quite possible that
those early populations were limited by predation and traumatic
injury.
In
that case, limiting reproductive output would seem to be very
unfavorable.
I realize that some of these hypothetical conditions, if they
obtained,
might tend to contradict each other, or cancel each other out, but I
nevertheless believe they indicate against ready acceptance of the
kin-selection mechanism.
Martin M. Meiss
2013/3/28 Mitch Cruzan <[email protected]>
This neglects that fact that homosexuality is not an accident of
history
or just a artifact of modern human societies. This trait is too
widespread
and occurs at too high a frequency in human populations to be
explained
by
chance - there must have been a selective advantage in the past. The
widespread nature of this trait across human populations suggests
that
it
must have been present in the human lineage by at least the time
of the
second major migration of hominids out of Africa around 60,000 ybp.
The
inclusive fitness argument mentioned several times by contributors to
this
listserve is probably the best explanation for the maintenance of
homosexuality in human populations.
Mitch Cruzan
On 3/28/2013 7:46 AM, Culliney, Thomas W - APHIS wrote:
I was referring to strict homosexuality in humans. Granted, there
probably are cases in which children of a (perhaps deceased) sibling
or
other close relative would be raised by a homosexual, thus
raising his
or
her inclusive fitness, but such cases would be rare. The Darwinian
fitness
of a strict homosexual is, as a rule, zero. Helpers at the nest do
forgo
their own reproduction to help relatives raise offspring, but, as
far
as I
know, there is no requirement for them to be homosexual.
Tom Culliney
From: Jonathan Colburn [mailto:[email protected]]
Sent: Thursday, March 28, 2013 10:05 AM
To: Culliney, Thomas W - APHIS
Subject: Re: [ECOLOG-L] Exclusive homosexuality
Hi Tom,
Respectfully, the Darwinian fitness sounds like inclusive fitness,
which
is often measured by reproductive success. However, reproductive
success
of a homosexual is not always a good measure of their inclusive
fitness
(e.g. helpers at the nest). Ultimately, any action that staves off
fixation of alleles to zero is about as close as we can come to
determining
that something is inclusively fit...
On Mar 28, 2013 9:20 AM, "Culliney, Thomas W - APHIS" <
[email protected].**gov
<[email protected]>
<mailto:Thomas.W.Culliney@**aphis.usda.gov<
[email protected]>>>
wrote:
I note that the albatross article mentioned the words "natural" and
"normal." Homosexuality certainly is natural, as it occurs in
nature,
in
animals from groups ranging from arthropods to mammals (who knows
what
goes
on in the plant kingdom?). In all cases, there appears to be an
adaptive
reason for the behavior. However, in its reproductive consequences,
exclusive or strict homosexuality, as exhibited in humans, cannot be
considered normal sexual behavior. The Darwinian fitness of
homosexuals
is
zero. To the extent that there is a genetic component to the
behavior
in
humans, with their diverse sexuality, the trait undoubtedly persists
in
the
population largely through the actions of bisexual individuals
leading
to
the production of offspring.
The above is an argument strictly from a biological perspective, and
is
not a moral judgment. What two consenting adults do in private is
their
own
business and no one else's.
Tom Culliney
-----Original Message-----
From: Ecological Society of America: grants, jobs, news [mailto:
[email protected].**EDU <[email protected]><mailto:
ECOLOG-L@LISTSERV.**UMD.EDU <[email protected]>>] On Behalf
Of
Kristen Dybala
Sent: Wednesday, March 27, 2013 10:55 PM
To: [email protected]<**mailto:[email protected].**EDU<
[email protected]>
Subject: Re: [ECOLOG-L] Expedition notice and question
Laysan albatrosses are a fairly well-known example. Here's a
(lengthy)
article describing it:
http://www.nytimes.com/2010/**04/04/magazine/04animals-t.**
html?pagewanted=all<
http://www.nytimes.com/2010/04/04/magazine/04animals-t.html?pagewanted=all
-Kristen
On Wed, Mar 27, 2013 at 6:53 PM, Merav Vonshak <[email protected]
<mailto:mer**[email protected] <[email protected]>>> wrote:
This story reminds me of a similar story - a male pair of Griffon
vultures (Gyps fulvus). They incubated eggs and reared other pairs'
youngs as part of a breeding in captivity effort in Israel some
years
ago.
Merav
Merav Vonshak
Postdoctoral Fellow
Gordon Laboratory
Department of Biology
Stanford University
Stanford, CA 94305-5020
Phone: 650-725-6791<tel:650-725-6791>
email: [email protected]<mailto:m**[email protected]<
[email protected]>
http://www.stanford.edu/~**mvonshak <
http://www.stanford.edu/~mvonshak
On 27, Mar2013, at 12:08 PM, Montblanc, Genie wrote:
WT,
Since I don't study this, I'm giving a, "What I've heard in the
news,"
response. There were two stories awhile back, both relating to
animals in captivity, about homosexual pair bonding. One was with
penguins, I think they also raised a chick together, and the other
was
with dolphins. Given that long-term pair bonding only occurs in
8-11
species in the entire animal kingdom, the question might be moot
anyway.
That is my inexpert response. Have a great expedition!
Génie
Eugénie MontBlanc
Great Basin Fire Science Delivery Coordinator University of
Nevada/Mail Stop 0186, Reno, NV 89557
Phone: 775-784-1107<tel:775-784-1107> (Fax: -1109)
Email: [email protected]<mailto:emb@**cabnr.unr.edu <
[email protected]>
Web: www.gbfiresci.org<http://www.**gbfiresci.org<
http://www.gbfiresci.org>
Twitter: @GBfirescience
-----Original Message-----
From: Ecological Society of America: grants, jobs, news [mailto:
[email protected]<**mailto:[email protected].**EDU<
[email protected]>>]
On Behalf Of Wayne Tyson
Sent: Wednesday, March 27, 2013 10:32 AM
To:
[email protected]<**mailto:[email protected].**EDU<
[email protected]>
Subject: [ECOLOG-L] Expedition notice and question
[NOTE:] I will be on expedition (with a stop at the National
Native
Seed
Conference in Santa Fe NM on April 10) until the two weeks at
the end
of April and the first week of May, then gone again beginning
the 2nd
week of May until around May 24. I will not be checking email
during
those periods, but will respond to as many email messages as
possible
during those hiatuses. A third expedition following those is
likely,
but the period of hiatus is iffy.]
Here is my parting question. Please feel free to post it on other
lists.
Re: Homosexuality in animals other than Homo sapiens. We know that
homosexual behavior occurs in other species in some forms (Bonobo
chimpanzees [Pan paniscus], for example), and we know that
hermaphrodites of some species fertilize each other simultaneously.
But my question is in which species other than humans, does
EXCLUSIVE
homosexuality, especially in the form of pair bonds, occur?
WT
I'll pick up my answers in late April. If I have time, I may be
able
to
respond to some today. Please respond on-list, and not to me
personally.
--
------------------------------**----------------------------
Kristen Dybala, Post-doctoral Researcher Museum of Wildlife and Fish
Biology University of California, Davis [email protected]<mailto:
ke
**
[email protected] <[email protected]>>
(415) 218-9295<tel:%28415%29%20218-9295> - cell
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