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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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17 votes
2 answers
5k views

Do males of all sexual species have Y chromosomes?

I know for instance some cells are sexual, so, this got me wondering, do the males of all species that have distinct sexes have Y chromosomes?
Stan Shunpike's user avatar
35 votes
3 answers
6k views

What's the difference between male and female?

As long as we only look at humans the differences are clear: males have chromosomes XY, produce sperm and don't get pregnant. Females have chromosomes XX, produce egg cells and bear babies. But when ...
user15004's user avatar
  • 361
5 votes
3 answers
5k views

Is sex a spectrum?

At the moment I'm especially interested in the question of whether biological sex is really a spectrum. Unfortunately I could not find any good answers on the Internet. Therefore I hope that some of ...
Tetragrammaton's user avatar
9 votes
3 answers
2k views

Is homosexuality an adaptation in humans?

Homo sapiens have menopause - as some other mammals (e.g. some Cetacea) - a phenomenon where older females live for decades after the end of their own reproduction. Perhaps homosexuality, that looks ...
Rodrigo's user avatar
  • 1,300
6 votes
8 answers
8k views

Does any animal species have two sexes and more genders?

Are there any animal species that have two sexes and a kind of different internal diversification in two genders or more? I don't mean something like different-task-based diversity, but something ...
lalessandro's user avatar
2 votes
1 answer
421 views

Does recombination increase the additive genetic variance for fitness?

On this article, first column, eighth line of the introduction: By bringing together favourable alleles from different chromosomes, sex and recombination increase the additive genetic variance for ...
Remi.b's user avatar
  • 68.1k
2 votes
2 answers
22k 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 ...
Beginner's user avatar
  • 169
19 votes
1 answer
119k views

What is the female equivalent of the morning erection that some men experience?

There was question about what causes "morning wood." It was answered that the erection in the morning is caused by decline of norepinephrine during REM sleep. Which in part allows to prevent ...
jnovacho's user avatar
  • 363
7 votes
1 answer
527 views

Can you tell the sex of a white willow when it's not flowering?

Can you tell whether a salix alba tree will produce male flowers or female flowers by looking at it, touching it or generally using your unaided senses? If not, is there any way to do that without ...
ymar's user avatar
  • 680
4 votes
1 answer
342 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 ...
Chill2Macht's user avatar
4 votes
1 answer
243 views

Evolution of the haplo-diplontic life cycle

From wikipedia > Biological Life Cycle: haplontic life cycle - the haploid stage is multicellular and the diploid stage is a single cell, meiosis is "zygotic". diplontic life cycle - the diploid ...
Remi.b's user avatar
  • 68.1k
3 votes
1 answer
212 views

Evolution from Mating types to different sexes

Imagine a lineage of multicellular organisms that had mating types and evolved their mating types into sexes. What are the possible mechanisms that might have brought this lineage to evolve sexes from ...
Remi.b's user avatar
  • 68.1k
2 votes
2 answers
2k views

Can animals, like monkeys, be homosexual?

I heard that some monkeys can be homosexual? a friend of mine was saying that he saw a male monkey having sex with another male monkey in the zoo, I honestly didn't believe him, I think he just got ...
user avatar
1 vote
1 answer
177 views

Which species has the highest proportion of homosexual individuals?

Are there more homosexual individuals in ducks, humans, or some other species?
user37015's user avatar