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17

Yes the males of a group of bony fish Syngnathidae can bear offsprings or as you say produce offsprings. This group includes Seahorses and Pipefishes. In some species the male have either a brood pouch attached to the trunk or its tail while in others the egg is attached to the trunk or tail laid by the female.The fertilisation takes place in the pouch or in ...


12

The concept of transgenders has nothing to do with sexual organs at birth. Transgenders is a concept that has to do with sociology, not biology. See the wiki link. intersex (previously called Hermaphroditism) has to do with biology. The wiki link makes a great job at defining intersex. In short: A transgender person is born anatomically either male or ...


7

Medical science has reached the point where it is able to consider performing uterine transplants in genetically female (cis-female) patients born without a uterus. In the MedlinePlus report, First Uterus Transplant Planned in U.S. doctors at The Cleveland Clinic have plans to perform the first uterus transplant in the US sometime in 2016. The article does ...


7

Sex vs Gender Sex is defined by the anatomy of an individual. The majority of people can safely be categorized as either male or female. There are exceptions and limit-cases of course such as intersex people for example. Gender is a social construct. It is therefore not the role of a biologist but the role of a sociologist to address the details of the ...


5

It's true that the microbiome and microscopic structure of the neovagina are not the same as those of a natal vagina, although explicating this outside of circumstances relating to post-surgical dysfunction or pathology seems unnecessary and a potential source of discrimination. Whether post-surgical outcomes are "proper," as you put it, should be ...


5

Remi gives a good introduction to the various terms and definitions you should know when learning about gender identity. However, he didn't really address your basic question: What is biological difference between transgender and a normal male/female[?] Except for some likely genetic differences, which we aren't even close to beginning to understand, ...


4

Let's first consider the difference between the concepts of sex and gender. The distinction between sex and gender differentiates sex (the anatomy of an individual's reproductive system, and secondary sex characteristics) from gender, which can refer to either social roles based on the sex of the person (gender role) or personal identification of one's ...


3

Spotted hyenas are a matriarchal society and female hyenas are larger than males. Also, female hyenas dominate males.


3

It is definitely more than science fiction. Many species have sex determination that depend upon the temperature. As a rule of thumb, when it comes to sex, not much has been invented in fictions. The diversity of reproductive system is HUGE! I will not mention 1% of the existing complexity in sex systems. For simplicity, below I will limit my concepts and ...


3

Are more males born than females in humans? According to the CIA (the only reference I could find; see here click on "people and society" and look for "sex ratio"), the world wide sex ratio at birth is 1.03 males for every female. This sex ratio is reversed at old age (women's life expectancy is higher than men's). at birth: 1.03 male(s)/...


2

Parental care by the male parent is off course relatively common, especially in birds and mammals. Cases were the male actually does most of the 'breeding' are relatively rare. I think @Sanjuktaghosh gave a beautiful example, but there are a few more: Mouthbreeders keep there offspring in the mouth for considerable amounts of time. In most mouthbreeders, ...


2

I think that you will find that the opposite is the case more often. First of all, a premise that XX vs. XY has some kind of fundamental truth (which really is a premise of this question) is simply incorrect. There are a wide variety of karyotypes of the sex chromosomes, and these do not line up well with common notions of sex. Using the XX vs. XY heuristic, ...


1

Whatever is the exact definition of the threshold that the Olympic committee sets, it's going to be relatively arbitrary and unfair to some people. When it comes down to it, biology is generally messy and blurry, and that includes matters of sex and gender. Thus, even if most people cluster in a fairly straightforward manner into male and female, there are ...


1

The idea that males and females react differentially to various smells in the context of “hard science” alludes to the concept of sexual dimorphism in olfactory signaling, which has been investigated: Stowers & Logan. Sexual dimorphism in olfactory signaling. Current Opinion in Neurobiology. 2010. 20,770-775. What makes males and females ...


1

Some behavior can be traced to the genome. In Drosophila there are many interesting studies that show how genes and courtship behavior are related Example. In mammals, the environmental component in determining courtship behavior is for sure, much more relevant than in Drosophila.


1

To my knowledge, it is still mainly unclear what are the enviromental factors that would promote Environmental Sex Determination (ESD; incl. TSD) vs Genetic Sex Determination (GSD; incl. with and without sexual chromosomes). Environment variability and Climate change Generally speaking it is thought that in variable environment, GSD might be more ...


1

You stated: 30% of twins are identical 50% of non-identical twins have the same gender Therefore 70% of twins are non-identical and 50% of those will have the same gender. I'll leave the rest of the calculation to you.


1

Yes During embryonic life,there is formation of new synapses by a process termed as exuberant synaptogenesis. Their differential formation in the males and females could be due to the effect produced by the gene PCDH11X/Y located in the allosomes. PCDH11Y is a gene unique to human males that encodes Protocadherin 11Y, aprotein that guides the development ...


1

Yes. What you are looking for is a meiotic drive, it's a genetic factor that favors its own transmission. Sex linkage is very common in these due to sex chromosomes not undergoing recombination. Once such driver, R2D2 (I shit you not) is a Y linked gene that drastically increases the number of male offspring in a mouse that carries it, to the point it can ...


1

The gametes produced by an organism are determined by the organism's sex - Thus, that statement from Wikipedia appears correct to me. In the case of humans, males have two different sex chromosomes. Thus, males produce gametes with either a Y-chromosome or an X-chromosome (XY). Female humans also have two sex chromosomes, but they are two different X ...


1

You may think about the reproductive success of a family, which depends on the reproductive success of sons and daughters. The reproductive success of the sons is theoretically unlimited, provided they are big enough to win many competitions. To get bigger, it's good to have a larger growth period. Thus, latter maturation. The (direct) reproductive success ...


1

Reproduction is kind of the definition of biological success. Logically, it works because it works because it works. Provided that the mother is responsible and healthy, there's a good chance the offspring will survive and reproduce. And since health and age are like opposing forces, the sooner a female develops and develops responsibility, the more likely ...


1

As already pointed out by Remi, you can identify the sex from a tissue sample only if there is a genetic (such as chromosomal) sex determination system (by using techniques such as PCR or in-situ hybridization). However, different species of fish employ different mechanisms of sex determination: Focus on or attachment to genetic systems involving X and Y ...


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