Apologize for the hijack, but I’m not seeing the connection in this context between soap-dropping and rape. I’ve always heard that as a lame joke about prison showers, but prison wasn’t mentioned.
In fact, as near as I can tell, it’s about bad eyesight: if you can’t tell men and women apart, don’t set down your car keys, lose something important, etc.
What was that supposed to mean, Jinx?
No, race is definitely a social construct. There’ve been many, many threads on this board.
I think that lissener meant to say that sex is biological rather than gender. It’s hard to say that the abilities to impregnate and be impregnated don’t have a basis in biology.
The two sexes are a useful concept for a very large proportion of humanity, but the problem arises when it isn’t and people act as though it must be.
It is interesting to note how this board has changed over the last many months and the posts are much more populated by folks offering opinion as opposed to informed statements. My impression is that there are fewer and fewer experts weighing in on matters here and more and more WAGs being tossed around. I’m not sure why that is, or even if that’s true. Maybe it’s just the impression that I’ve gleaned from the few threads that I’ve looked at. However, Colibri, or others who are biologists or scientists who are truly well informed can certainly give us some firm foundation on which to base some discussion. FWIW, I believe the whole notion of the development of sexual reproduction is a significant issue in the field of the history of biology. The development of sex is a significant point in evolution. Why it happend is probably a point of interest, debate and discussion among biologists today, but the fact is that there is little doubt that among plants and animals, at least, maybe some fungi (?), there exist male and female sex cells - i.e. sex cells. They are different, and must unite in order for the species to reproduce. There must be a mixing of genes from different organisms and consequently a new set of genes is introduced into the population. This is a significant change from the previous business of cellular reproduction in which the nucleus simply split and formed another one just like the other one. So, yes, there are different sexes in that sense. How that plays out in human social interactions is a different matter and is, as has been mentioned above. And, how it is expressed physiologically is also a large and complex matter - see, for example endocrinology, psychology, brain physiology, etc. etc. The question is far too broad to be addressed in a simple forum such as this.
It took two and a half months to come up with this question? 
No. And while “race” as it is used in the US is a social construct, and while the traditional races of caucasoid, negroid, mongoloid and so forth don’t have any real scientific validity, it is possible to distinguish human populations on a smaller scale (although these do intergrade with one another as well).
No, because it is not a smooth continuum. The vast majority of humans (and other vertebrates as well as many other animals) are in fact clearly male or female. While intermediates occur, they are a very small part of the population. Furthermore, many intermediates are sterile and unable to function as either sex. Claiming that males and females don’t exist is a bit like claiming that breeds of dogs don’t exist because mongrels occur, or that horse and donkeys don’t exist because mules can be produced.
Many species of fish are hermaphroditic. Some are sequential hermaphrodites, starting out as one sex and then changing to the other as they become larger. But males and females clearly are distinguishable in these species, even though the same individual may be both at different stages of its life - it just takes on a different functional role.
A few species of fish are simultaneous hermaphrodites, being both male and female at the same time. Here of course separate sexes don’t occur. However, in a mating bout each individual will alternately take on a specific sexual role, producing eggs while the other produces sperm, and then switching roles on the next bout. Therefore specific sexual roles exist even in such species.
I’d disagree with that. Since I’ve been on the board it seems to me that there has been just about the same ration of information to speculation. In fact, I first joined the board more than five years ago because I couldn’t stand the amount of bullshit that was being tossed around in a particular thread. 
The statement said race is a social and linguistic concept. What is linguistic about race? The race a person is has nothing at all to do with the language they speak.
Gender is certainly a social construct, not biological. Yeah, sex is biological, but lissener didn’t say sex.
I interpreted it to mean that race is a matter of terminology, just the application of a set of words to an indifferentiuable concept- distinction without a difference. Hence linguistic.
So, not to do with the language spoken by the individual or group, but the language used about the individual or group.
And the OP said nothing about gender - you were the one who introduced that term to the thread. The OP merely asked about sex, not gender, and it is unclear whether he was limiting his question to humans or meant to include animals and plants as well. Since he is banned, it is unlikely we will get a clarification on what exactly he had in mind.
Your first instinct may have been correct, since you seem to be introducing issues not explicit in the OP. Whether they were implicit cannot now be determined.
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With all the differing opinions offered here, I think this has moved into IMHO territory.
Moved.
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I’m going to give this a factual answer anyway.
The “default” sex is female. When two organisms reproduce asexually the resulting organisms, clones, as referred to as “daughters.” The original state was asexual reproduction which, on the surface, is more beneficial than sexual reproduction. Sexual reproduction is a less effective means of increasing a population. In asexual reproduction all daughters can give birth but in sexual reproduction only about half of the population (females) can give birth. Furthermore, sexual reproduction carries risks - a creature must find a mate (not always an easy task), convince the opposite sex to be their mate (I think we all know the difficulty of this one), mate (sex can sometimes result in violence or death), and produce a baby which is composed of the DNA of a different individual as well as your own.
So how come the vast majority of eukaryotic species reproduce sexually even when asexual reproduction is available to them?
Genetic variation produces a healthier population. In populations where there is less variation (due to asexual reproduction) the offspring produced are sicklier than those produced by sexual reproduction.
In humans, there is no consensus on what makes someone a male or female because there are three markers – chromosomes, gonads, and genitals. In humans, males are produced by a gene that is found on the Y chromosome (although in rare cases it can be found on the X). This gene causes the body to become awash in male hormones and male gonads develop (testicles). Because the genetic default is female, if the androgens do not bind properly, it will have no effect and a female will develop despite having XY chromosomes (AIS). In other words, if you consider chromosomes to be the end-all determinants of sex, then some males will have vaginas. It is important to note that it is impossible for an intersexed individual to have both male and female gonads unless they are a chimera with two distinct sets of DNA. In other words, true hermaphroditism resulting from one set of DNA is impossible in humans. There is clearly a difference between male and female in humans, although some individuals fall inbetween.
Further complicating matters, the Y makes a male rule does not apply consistently throughout the animal kingdom. In fruit flies, two XXs will result in a female and anything else in a male. While in humans XO makes a female, in fruit flies a male is created. In birds, XX (or ZZ) is male and XY (or ZW) is female. In some animals that don’t have sex chromosomes, a fertilized egg becomes a female and an unfertilized one a male.
Now, as for looks, males and females look different because of sexual dimorphism which is differences in sexes due to secondary sexual characteristics. In some species sexual dimorphism creates males and females which look like they belong to two separate species. Male gorillas and orang-utans weigh twice as much as their female counterparts. Male chimpanzees and bonobos are about 1.35 times as heavy. In, early homo, sexual dimorphism shrank so that modern human males are about 1.2 times the weight of human females. In primates, pronounced sexual dimorphism is often parallel with competition of a small amount of dominate males for many females.
Although our sexual dimorphism is small, all children can tell the difference between males and females at a very young age.
So that’s sex, I won’t even begin to get into gender. It’s a shame that this thread was hijacked so much because it is a very valid question.
In case anyone wondered what ancient gays had to do with anything, the “homo” is supposed to be Homo.