Whenever I see lesbians on tv or in public, it seems that they always
have more masculine facial features. A lot of them have more wrinkles
on their faces, rougher looking faces, and they look more masculine in
general. Has there been research to show that this is actually true,
and if so, what would the reason be? Is it a low amount of estrogen
compared to straight women?

I would not say that Samantha Fox looks or ever looked very masculine...

Just a thought that crossed my mind.
Scriptor

One's impression is subjective.  If one knows or believes a person of
either sex is homosexual  - or of some minority descent, etc. -  one
often "sees" features and/or mannerisms to support this impression.

During the second and third weeks of pregnancy if the embryo is to be
male the mother produces a very high amount of testosterone, this
testosterone gives the embryo a kick-start and the testes begin to
develop, from then on all the testosterone the embryo needs will be
produced by his own testes. The original production of testosterone by
the mother also gives the brain it?s basic structure with the physical
connections that the brains of males have. Later on this is further
developed by the embryo?s own testosterone?s influence. If the embryo
is supposed to be a female there is no extra production of
testosterone by the mother and the embryo continues as it was (we all
start as female zygotes, males are the consequence of the evolution of
sexual reproduction).

If the mother happens to produce this extra amount of testosterone
during the second and third weeks of pregnancy as if the embryo was to
be a male, it will ?wire? the brain of the female embryo as if it was
that of a male. Since the female lacks testes it will not produce the
necessary testosterone to turn this embryo into a male and it remains
a female, although the basic wiring of the male brain has already been
done. In effect you will have a male brain (acting as such, being
attracted to females, more adept at certain tasks etc.) trapped inside
a female body, that gives you the phenomena we know as lesbians. For
gays the exact opposite is true, the mother fails to produce the
necessary testosterone at the right time, and although the embryo?s
own testes will later produce the testosterone that turns the embryo
into a male it already has the basic wiring of a female with all it?s
attributes.

Later contributions of hormones either male or female will only
replace the normal amounts needed in the body not add to them. For
instance, if a normal male is injected with testosterone, his testes
will stop producing it so as not to have an overabundance of the
hormone. In fact, if the treatment is prolonged the testes will
shrink. So, no masculine or feminine physical characteristics should
be attributed to one or the other since the effect is not the result
of current hormonal levels but the levels of testosterone the embryo
was exposed to between the second and third weeks of pregnancy, long
before any features were developed.

Although I present this as fact it has not yet been proven. However,
in my mind it is the most likely explanation, among others it explains
in a very simple manner why homosexuality persists although it is
something that natural selection forces would?ve eliminated eons ago.

Many of the lesbians I have known have worn little or no makeup. This
might make them appear less feminine in a culture in which shiny red
lips, fake pink cheeks, and exaggerated eyelashes are seen as signs of
femininity.

I know it's "only a movie," but ...

http://www.gaycitynews.com/gcn_360/lesbiandrama.html

I vaguely remember reading something written in the 1930s, suggesting
that female cousins/sisters who lived together were not as 'related'
as they let on.

I suspect that our impressions are biased by 'aggressive' displays of
sexual preference

Once an interesting woman who had spent a lot of time in Saudi, said
that 'the men are pigs, but the women don't care - as they are into
each other'

While one can judge a book by its cover, it is not a very reliable technique.

I think the many of the differences that you are seeing on TV has to
do with what Hollywood producers think Lesbians look like. In my
social interactions with lesbians I have found a much larger
'comfortable shoe' type look that would frequently hang out together,
but I know too many lesbians that do not share this look to think it
is a lesbian 'trait'. I do think your question is interesting though
in respect to 'gaydar'. What is gaydar? How do I know when I am
discussing what kind of coffee to get with someone at the grocery
store do I know that they are likely gay? Sometimes it is dressing in
a way or a kind of grooming that indicates that they may be gay, but I
just don't believe this is all there is to it.