Posted on alt.usage.english a while ago:

[...] Relatively fewer women -- from a third to a half as many --
call themselves lesbians compared with men who identify as gay.
                   -- A political scientist in _The New York Review_

Now, class --

This fellow did have a problem, tho it probably didn't seem like one
to him. He had yoked together "fewer", which calls for "than", and
"as many", which calls for "as". His solution was to use that piece
of syntactical duct tape "compared with", which, come to think, he
might have used anyway. I sympathize. The variety of linking words
required by the various idioms of comparison in English *is* a
frequent nuisance, and must be a puzzle to learners:

as big _as_
bigger _than_
similar _to_
different _from_ (or so say the school grammars)
the same _as_
other _than_
equal _to_

etc. Every time you want to use two of those constructions together,
you have to either tread on the toes of one of them or resort to a
wordy & pointless contrast-within-a-contrast. If I were dictator, I
would be tempted to level them all -- probably to "than".

In the real world, I would say that the parenthetic construction has
less claim on the following syntax than does the initial one, and I
would lay down (if not as a rule of grammar, then as a rule of
stylistic hygiene) that comparatives should never be followed up with
anything but "than". There is a special reason to avoid "compared
to/with" after comparatives: It results in (and perhaps results from)
a confusion of two usefully distinct idioms:

The force on the earth due to Mars is smaller than that due to the
sun.

The force on the earth due to Mars is small compared with that due
to the sun.

The second statement is properly a much stronger one, roughly
synonymous with "...*much* smaller than...". It suggests that the
smaller force is negligible as a first approximation.

So I would try my luck with

Relatively fewer women [...] call themselves lesbians than men
identify as gay.

Well, not really. With some of the trash cleared away, the Elegant
Variation stands out in all its distracting silliness. "Identify as"
-- here, at least -- means the same as "call themselves". No problem,
for me, deciding which to get rid of (I think Erik Erikson was a
crackpot):

Relatively fewer women [...] call themselves lesbians than men
call themselves gay.

And now, off with its head! "Relatively" before a comparative is
usually open to the same objection as "compared with" after one -- it
mixes & confuses two constructions that ought to be kept distinct:

The moon's gravitation is the main cause of the tides; the effect
of the sun is smaller.

The moon's gravitation is the main cause of the tides; the effect
of the sun is relatively small.

The business of "relatively" here is to clarify the bearing of "small"
by harking back to the preceding clause; "relatively small" is short
for "small in relation to that of the moon". That is not quite the
same, in emphasis anyway, as "smaller"; it suggests a classification
(with the moon as standard) rather than a mere description, and it
implies *considerably* smaller.

I did say "usually", and I can imagine meaning something by
"relatively fewer":

Smoking causes most cases of lung cancer; it causes relatively
fewer cases of heart disease.

That might mean: In actual numbers, smoking may cause more heart
disease than lung cancer, but there is so much more heart disease that
smoking is more prominent in the cancer statistics. Yes, I can
imagine it, but I wouldn't write it. Slovenly use of "relatively" has
been so common for so long that most readers couldn't be trusted to
take it seriously. They would skip over it as they would a drool on
the page. Better make it "a smaller proportion of the cases of heart
disease".

In any case, such a use would be otiose in the present example,
because the numbers of men & women are near enough equal that relative
& absolute comparisons amount to the same thing.

So:

Fewer women -- from a third to a half as many -- call themselves
lesbians than men call themselves gay.

By now the parenthesis has become painful, not only in its discordant
syntax but in its interruption of the clause. One could remedy the
first problem by changing the parenthesis to "by two-thirds to
one-half", but that makes the second problem even worse, because the
reader has to stop & figure out what it means. I would be inclined to
remove that information to another sentence, or, indeed, make it

Fewer women call themselves lesbians (x to y percent) than men
call themselves gay (z to w percent).

-- whatever the numbers are.
--
--- Joe Fineman    jcf@TheWorld.com