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Questions tagged [sex]

Questions involving the study of sex and reproduction, mating systems, sexuality, sex determination, gender, the evolution of sex, and other topics in the context of sex.

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Is male cosmetic surgery a viable mating strategy for choosy females?

Is a man in modern times "competing" with other men based on genetics for reproductive success? If so, would male cosmetic surgery of any degree be viable as a modern attempt at competing for female ...
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1answer
43 views

Can diet, supplementation and/or drugs affect sexual dimorphism?

After puberty, can certain diets, exercise, and/or possible drugs affect masculine/feminine dimorphism in adults? We know dimorphism and/or morphology is a product of genes, but to what extent can ...
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35 views

Are humans the only primates being engaged in group sex?

There are quite many examples of humans being involved in group sex. I won't say it is a common thing and won't say whether it is "natural" or "cultural" (but "cultural" only means induced to majority ...
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2answers
92 views

In men, why do over 80% of sperm have abnormal form? [duplicate]

Here is the percentage of normal forms among fertile mens according to the centile (Source: Cooper et al. 2010): 2.5: 3% 5 (below this is Teratozoospermia): 4% 10: 5.5% 25: 9% 50 (median): 15% 75: ...
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0answers
19 views

What fraction of species representatives is needed to say they have dispersed mating model?

Many biologists adopt the following division of mating systems: monogamous (and sometimes serial monogamous); polygynous; polyandrous; promiscuous/polygynadrous (sometimes distinguished as separate); ...
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0answers
21 views

How is sex determined for drosophilia flies?

I am confused on Drosophilia sex determination. Here is what I understand: The X chromosome has the sxl gene. Flies with 2 X chromosomes are able to produce ...
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3answers
4k views

Why do hot water baths affect only males' fertility? Why not females'?

Here is the link where urologists are warning men not to take hot water baths. Why does it affect only males' fertility? Why not females also?
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4answers
383 views

Are there lifeforms that have more than 2 sexes?

Are there any lifeforms on earth that have more than male and female biological sexes? If so, are all three mates required for reproduction or is there something else going on? If not, why not? ...
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1answer
70 views

Is it Theoretically Possible to Create a Male clone from the donor Cell of a Female?

I understand that Dolly the Sheep was created without the presence of a sperm cell. Instead, nucleus DNA from somatic cells of adult sheep were used. Since Dolly was female, i am assuming that the ...
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1answer
165 views

Do reproductive organs function before puberty?

Testis means one of the two male reproductive glands that produce spermatozoa and secrete androgens. Ovary means one of usually two organs that produce oocytes and secrete oestrogen and progesterone. ...
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0answers
83 views

Do ovaries produce estrogen before menarche?

It is traditionally taught that estrogen is produced by the granulosa cells of the follicle. But before menarche, where does the estrogen come from? Is it from the thin layer of granulosa cells lining ...
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1answer
71 views

Why are worker ants not clones of the queen?

Currently worker ants of most species share only three quarters of their genetic code. It seems like worker ant clones would be better, as it would remove all genetic conflict of interest between them....
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149 views

Effect of Testesteron and Estrogen on adult opposite sex?

I know that if Estrogen is given to a teenage male then it triggers the development of secondary sexual characters of a female the male body, like breast growth and other. and similar happens if ...
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0answers
52 views

Which scallops change their sex from male to female?

Tonight it occurred to me to look up what scallops are like when they are alive (beyond their culinary role) and it blew my mind. This post regards one detail about which I was unable to find specific ...
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1answer
127 views

Sex determination in cephalopod?

I see some source say octopus do not have sex chromosome. So what's the Sex determination mechanism for cephalopods? Thanks.
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0answers
21 views

What Could Cause a Skewed Sex Ratio in Humans? [duplicate]

I know that slightly more men are born than girls, but what could cause the birth rates to change so that the number of male births is at least, say, 50% higher than it is now? What could cause the ...
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1answer
14k views

How many genders are there? [closed]

These days it is often contested how many genders is there. So my question is how many genders is there and is it unnatural for evolution to generate multiple genders.
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2answers
225 views

Can you tell if a corpse was male or female by only examining its skull?

There are articles that says women have more rounded corner faces than men, than women noses are usually shorter, etc. But are those (and other features) tendencies or deterministic features that ...
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1answer
456 views

Does orgasm cause a dopamine crash?

There's some theory around that orgasm will cause a dopamine surge and drop, and that this can lead to a period of low mood or depression. A come down. Is this true, does orgasm have a negative ...
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3answers
23k views

Are male and female brains physically different from birth?

Male and female brains are wired differently according to this article: Maps of neural circuitry showed that on average women's brains were highly connected across the left and right hemispheres, ...
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0answers
52 views

Number of alleles' variations in a mushroom that has over 20,000 sexes

I am trying to understand the mating behavior of a particular species of fungi known as Schizophyllum commune, or the split-gill. I found a blog post that explains the mechanisms that define the ...
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0answers
892 views

How does temperature affect sex drive in humans?

I've ran into a science journalism piece which reported on a NBER study fidning that lower human fertility following hot temperatures over 80 degrees Farhenheit. They attributed this effect to ...
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1answer
72 views

Which species has the highest proportion of homosexual individuals?

Are there more homosexual individuals in ducks, humans, or some other species?
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0answers
237 views

How Excessive masturbation can make a person unfit for army? [closed]

Recently I saw this news trending, I never heard single disadvantage regarding masturbation. But China Army considering it has danger for army. So How Excessive masturbation can make a person unfit ...
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2answers
841 views

Why boys who inherit more genes of their mother are not born as girls and girls who inherit more genes of their father not born as boys?

If boys as well as girls inherit the genes of the father as well as mother, does it imply that boys inherit more genes from the father to be boys and the girls inherit more genes from the mother to be ...
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0answers
276 views

Why females don't have much sexual desire when compare to males? [closed]

I read this Wikipedia article about Playgirl, It is made especially for females. but Its Spokesman Daniel Nardico revealed subscriptions are generated more from males. In a February 2010 interview ...
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1answer
178 views

Is there a theoretical maximum on the number of sexes a given species can have?

Background: To the best of my knowledge, most sexually-reproducing species of organism have two sexes, although there are also sexually-reproducing species of organism (flatworms come to mind) which ...
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2answers
116 views

What are the distinct neurochemical components of sexual pleasure?

Sexual activity is usually described as pleasurable. What neurochemical systems does sex activate? Does the presence or absence of a partner make a difference -- say, in the activation of the ...
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2answers
348 views

Why would a human female have a sexual display despite male biased operational sex ratio? [closed]

why would a human female have a sexual display despite male-biased operational sex ratio? In human society there is a male-biased sex ratio, due to female child rearing, which results from anisogamy. ...
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1answer
51 views

Why human endometrium doesn't stay constant? [duplicate]

Is there any explanation or evolutionary advantage to the endometrium constantly cycling between the proliferative and menstrual cycle? Wouldn't it be more advantageous if it kept always fully ...
5
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1answer
166 views

Are all non-breeding naked mole rats the same sex?

In many eusocial species, all the non-breeding members are the same sex. Honeybees are a good example, with only female workers. Are naked mole rats that do not breed also all either male or female, ...
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0answers
77 views

Are oysters really aphrodisiacs?

Oysters have been thought of as aphrodisiacs for millennia. Is this a case of the bark of a willow tree as a precursor to modern paracetamol, or some sort of marketing ploy. Is there any biological ...
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1answer
210 views

How spinal cord play its roles in human beings sex? [closed]

I know most people can't enjoy sex if their spinal cord injured. How spinal cord play its roles in human beings sex?
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0answers
200 views

Where does new blood comes from when penis get erected? [duplicate]

In Humans, During sexual arousal in males, his penis will get erected with blood. Where does this new blood coming to fill his penis which is required for erection ?
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1answer
569 views

Are humans not sexual dimorphic? Can genetic XY but SRY not expressed become pregnant? [closed]

My understanding was that XX/XY was how sex is determined in mammals, and so humans as well. A science teacher posted this regarding transphobia: "I just commented this on a transphobic post that ...
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1answer
5k views

Is female the default sex in humans?

I was taught in school that female is the default sex in humans based on the following logic: Development into a human male requires the activation of the SRY gene in the foetus. If that doesn't ...
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1answer
59 views

Is the term 'allele' specific to sexual populations?

I had always thought that 'allele' simply meant a variant of a gene and thus could be used in the context of either asexual or sexual populations. With it only being slightly less useful as a concept ...
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2answers
10k views

What's inside the males body in the space where females have the ovaries and the uterus?

The male penis and scrotum are external extremities, whereas the female sex organs are placed "inside" the body. So as females have the bladder, rectum, other stuff just like males. Does this mean ...
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1answer
829 views

Why do women mature (physically) earlier than men? [closed]

All sources I've read (the first page) states that the fact that women mature (in the sense of physical maturing) earlier than man is caused by the earlier selective prunning in brain. Though, this is ...
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2answers
14k views

How is trangender female different from normal female biologically?

I have read in many places that transgender people are usually people who are born with typical male or female anatomies but feel as though they've been born into the “wrong bodies.” The thing that I ...
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1answer
119 views

Is there any evolutionary reason for why some organisms (wrasse) change their sex in adult stage?

In San Francisco, I saw this fish: and quoting the aquarium's page: Part of the wrasse family, the California sheephead is a protogynous hermaphrodite. Simply put, all sheepheads are born as ...
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1answer
141 views

Stem cell and organ growing genitals [closed]

I've been reading a lot about stem cell research and the work on growing artificial organs. I assume, with sufficient advance in the technology, there is no theoretical reason it would not be ...
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0answers
100 views

Why does female's age of puberty inform on mating system?

Reading from Does increased calorie intake cause increase in libido in humans?, @AlexStone says: I'm aware that humans have a dual mating strategy - somewhere between pair bond and casual mating. ...
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1answer
3k views

What is the evolutionary advantage of having pubic hair?

Only humans have pubic hair. What is the evolutionary advantage in having it?
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1answer
3k views

Why do people find anal sex pleasurable? [closed]

First of all, anus is not a genital part like vagina and therefore pleasure due to anal sex should not have any fitness advantage. I wish to know why many people find anal sex pleasurable when it ...
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2answers
644 views

Are there genes in sex chromosomes that determine facial features?

My friends and I were bored enough to try out this activity. Picture a teenage boy in your mind. From this picture, remove any accessories (glasses, piercings, etc.), moustache or beard, then ...
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1answer
2k views

Why do humans masturbate? [closed]

Why does masturbating seem to be like an addiction? What controls or initiates the urge to masturbate? Is it good or bad or both and why is it so? I have heard guys who say that the do it ...
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1answer
473 views

Acrosomal enzymes and the female reproductive tract

My textbook wrote that the reason why acrosomal enzymes are so securely contained within the sperm (thus needing capacitation to facilitate their release) is to prevent any premature release in the ...
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2answers
1k views

Are gametes determined by the sex of an organism?

In the Wikipedia article for biological sex, I read the following sentence. "The gametes produced by an organism are determined by its sex:..." However, is it not through the gametes produced by ...
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1answer
499 views

Are there animal species with sex of an offspring determined by sex of preceding offspring?

For instance, if an animal's first offspring is male, then all subsequent offsprings will be male too (the sex of first offspring could be determined randomly). Does it happen in any species?