From: jfh@greenber.austin.ibm.com (John F Haugh II)
Newsgroups: soc.motss,soc.bi
Subject: Re: Evolutionary reason for homo/bisexuality?
Date: 8 Apr 92 23:42:44 GMT
Organization: Best Care South of the Red River, LCC, Austin, Republic of Texas

In article <xrpjqmj.rich@netcom.com> rich@netcom.com (Richard Poppen) writes:
>Recently I've found myself speculating on a question that,
>surprisingly, I haven't seen discussed here:  What is the evolutionary
>reason for homo- and bisexuality?
>
>I am not asking "What causes homosexuality in an individual?"  That
>question has an answer like "this gene right here" or "a level of
>compound X above y ppm in the mother's bloodstream" or "a childhood
>environment that has attributes A, B, and C," or some combination of
>such answers.  It might be an interesting question (as might, say,
>"what caused my brown eyes?" or "what caused my SO's talent for
>learning languages?"), but it's not what I'm asking.

Homosexuality can be induced in lab animals by increasing the stress
in the environment.  It may be that homosexuality is a survival
response intended to reduce stress (food shortage, overcrowding, etc.)
or that in a stressful environment, competition for mates simply causes
some individuals to behave homosexually.  But if homosexuality is a
survival trait that is supposed to reduce the population, it would be
one that was beneficial to the species and might slip into the genetic
code.

>Our species spent has spent most of its time--most of the time from the
>advent of H. sapiens to now--evolving in an environment in which traits
>that impair the ability of their bearers to survive to reproductive
>age, or to have a large number of offspring, tend to be selected
>against.  On the face of it, it seems that homosexuality would be
>selected against.  If you spend some significant part of your limited
>sexual time and resources with motss, you won't have as many offspring;
>the offspring that carry the capacity for homosexual behavior won't
>have as many offspring; ...; and your genes will lose.

You are looking at genetics and evolution in too simple of terms.  If
I have a trait, it can affect you (and thus the entire species) in a
positive manner, even if I never reproduce.  Say, for example, that I
have a gene which in 1 out of 10 carriers causes them to be rocket
scientists.  Imagine there is another population group which has no
carriers of this gene.  In the 1 in 10 chance, I become a rocket
scientist and make your life much better for you (satellite TV being
what it is ...)  You reproduce, passing on this un-expressed gene and
since your life is so much better than the people without satellite TV,
you have more kids and this gene eventually speads to the rest of the
population.  I don't have to have a single child so long as being a
non-reproductive science nerd doesn't outweight the increased
reproduction your being a cable TV junky causes.

The same could happen with a gene that makes homosexuality possible
in the species.  Your being (or not) gay makes it more likely that the
population will grow less rapidly and that those sibblings of yours
who also carry the gene reproduce and propagate the trait.  If another
tribe of early humans lacked this gene, they might die from disease and
starvation while you were happily moderating your own tribe's growth and
increasing your genetic dominance.

>But that doesn't seem to be what's happened.  Homosexuality was around
>at the beginning of recorded history, when having lots of offspring was
>still important.  (Indeed, it still is, for the survival of your genes;
>just not for the survival of the species.)  So the capacity to be
>homosexual must have some indirect (i.e., not just reproductive)
>evolutionary advantage, or be linked to some other trait with an
>evolutionary advantage.  (For example, it could be in some way like the
>gene for sickle-cell anemia, which also increases resistance to
>malaria.)

"Having lots of offspring" hasn't always been as important as you might
think.  There are countless examples of infanticide throughout history
and changes to laws to reduce infanticide for the sole purpose of
increasing the population.  Remember that homo sapien is a species that
is able to bear children pretty much at will, and that these children
take several years before becoming self-sufficient.  If I were an early
cave man and my mate just had our 8th kid, and I barely had food to feed
the first 5 or 6, I'd likely kill the weakest child I had before I figured
out (20 or 30 millenia later ...) how to practice the rhythm method.

Homosexuality may well have direct and reproductive advantages.  Your
sibblings have about the same genes as you.  If you are gay, and your
sibblings (who have the same basic genes as you) aren't competing with
your offspring for resources, you have just increased the likelyhood
that you genetic code will be passed on.

>Does anyone know of any actual research related to this, or have any
>speculations?

Little.  There was a study of homosexuality in German males born
during WWII which found an elevated incidence.  Rats in small pens
with too little food is another favorite.

>(Btw, can one hope that anyone who would jump in exclaiming that
>homosexuality is unnatural, though it _obviously_ occurs in [human]
>nature, won't believe in evolution either?)

Stealing cars is natural.  Other species exhibit a tendency towards
theft.  Does this make it "good"?  Natural and a result of evolution,
sure.  But "good"?  No.  Arguing from nature isn't going to get you
anywhere but frustrated.  Dolphins appear to "rape" other dolphins.
Try arguing that rape is natural and normal to a rape victim.
-- 
John F. Haugh II      | VNET: LCCB386 at AUSVMQ | "Physical Fitness is the
SneakerNet: 042/2F068 | MaBell: (512) 823-1078  |  basis for all other forms
Internet: jfh@devnet.la.locus.com               |  of excellence"  -- JFK