is it true we all start off female?

Question

I heard somewhere that we all start off female in the womb. So I was wondering if anyone knew the answer to that.

Answer 1

In a way, yes. It could be more accurately described as "neutral"

A few weeks after fertilization, the initial appearance of the human fetal genitalia is basically feminine: a pair of "urogenital folds" with a small protuberance in the middle, and the urethra behind the protuberance.

In typical fetal development, the presence of the SRY gene causes the fetal gonads to become testes; the absence of it allows the gonads to continue to develop into ovaries. Thereafter, the development of the internal reproductive organs and the external genitalia is determined by hormones produced by fetal gonads (ovaries or testes) and the cells' response to them.

If the fetus has testes, and if the testes produce testosterone, and if the cells of the genitals respond to the testosterone, the outer urogenital folds swell and fuse in the midline to produce the scrotum; the protuberance grows larger and straighter to form the penis; the inner urogenital swellings swell, wrap around the penis, and fuse in the midline to form the penile urethra.

If testosterone is not present, normal female development continues, with the development of a perineal urethra and the formation of a uterus, clitoris and vagina.

The Müllerian ducts, which are paired ducts of the embryo which empty into the cloaca, and which develop into the upper vagina, cervix, uterus and oviducts; in the male they disappear except for the vestigial vagina masculina and the appendix testis.

Because of their common origin in fetal anatomy, a number of male and female anatomical features are said to be homologous; for example, the clitoris and penis are homologous with one another, as are Skene's glands in females and the prostate gland in males.

Most of the time, the result of fetal genital development follows the stereotypical male or stereotypical female development path. However, in a small but significant minority of cases, the path of development follows an intermediate or other pathway, leading to what are called "ambiguous genitalia", one condition of those known as intersexuality.

See congenital anomalies of the genitalia for a list of congenital disorders caused by problems with fetal genital development.

http://en.wikipedia.org/wiki/Fetal_genital_development

Answer 2

When the sperm meets the egg, the egg carries one X chromosome (sex-determineing gene), and the sperm can carry either an X or a Y chromosome. If the sperm carries a Y chromosome, the baby will be genetically male. If the sperm carries an X chromosome the baby will be geneticall female.

The sperm fertilizes the egg and these two haploid cells (containing only half of the genetic code necessary to creat a human embryo), combine their DNA to form a zygote. The zygote them implants itself within the uterine wall of the female. Anyway, many hormones are released and so on and so forth to stop the woman from menstruating or producing anymore egg follicles so that she doesn't get pregnant again while already pregnant.

The baby, regardless of its chromosomal DNA (X or Y chromosomes) will be sort of neutral. It will neither be male nor female exactly.

Around the second month of gestation, if the baby has an XY chromosome mix (genetically male), the Y chromosome calls on the Leydig cells to begin making testosterone which will increase the andorgen (male hormone) levels. This exposure to testosterone will cause the formation of the testes and related anatomical structures typical of males. In order to prevent a uterus from forming, the XY baby must also be exposed to AMH (anti-mullerian hormone which will stop the female sexual organs from developing).

Basically at week 7 babies have a urogenital groove. If the baby is exposed to androgens and AMH then it will be male, but if the baby is not exposed to these hormones, it will go on to develop female sex organs. So, we start out as neither really, but in the absence of any interference, females will be born, regardless of the XY or XX chromosomes.

Answer 3

No. That was the traditional view, but it is incorrect. An embryo with one X chromosome and nothing else (i.e. with Turner's syndrome) is not completely female; although female secondary sexual characters appear, the ovaries atrophy before birth and the individual will be sterile at birth. For the embryo to become a male, the SRY gene on the Y-chromosome has been found to be essential in stimulating testes formation and the development of male secondary sexual characters. However, for female gonads to develop, two copies of many X-chromosome genes (thought to be Wnt4 and Dax1, among others) are required.

Answer 4

It's true that embryo looks the same in the early stages of development, as females. Sometime during development, those embryos with the Y chromosome develop into male by the activation of the gene SRY (which is located in the Y chromosome) and produces the tests that will produce testoteron, which in turn will form the penis.

If SRY is not present (as in the case of females) the embryo will continue to develop as female.

Answer 5

The outside anatomy looks female early on, but the generative organs that make the distinction real don't form till the ovaries or testes start pumping out hormones that the cells respond to.

Answer 6

Hello, good question! The answer to that is we all start off assexual,no sex until months later when the distinction between male and female become noticable.The early stages of the fetus has no male organs but it doesnt have female organs or design either.In later stages the testes form and then drop and only later do the ovaries form in the female.Good day!

Answer 7

technically we all start predetermined by the chromosomes that were united. The rumor is because when the fetus is viewed through ultrasound during its embryonic development, the distinguishing characteristics of gender are not yet present, but some see it as it would resemble female. That is why there is a specific month where you can determine already the gender of the fetus. It counts at the 3rd month

Answer 8

Yes it's true. All embryos develop as female until a certain critical point in the process when, if there's presence of male hormones, then the genitalia develop as male. You could say, of course, "well if there's male hormones to begin with, then it was a male from the start." But what is meant by "we all start as female" is that if there were to be absence of male hormones, the embryo would develop with female sexual features/organs. So it's not the chromosomal sex (genotype) that's being talked about but the anatomical sex (phenotype). Or to put it differently, in some abnormal cases a baby can be born with female sex organs whose cells indicate it was supposed to be a male but for which male hormones did not get produced.

Answer 9

Yes. Each embryo develops initially as female, and if there is a Y chromosome present, the ovaries will drop and the clitoris will grow bigger.

Answer 10

How many ways can stars explode? At the most fundamental level, possibly ... core of a massive star, and thermonuclear disruption of a white –dwarf star. In the past .

Answer 11

genetically, no we don't. by the time we are conceived, our sex is already determined by the X and Y chromosomes.

Anatomically, sort of. All fetuses are sexually undifferentiated, have both early structures for the male of female organs.

descriptively, you can say that we start off "female" becuase the genital region isn't formed yet, and it looks like a vagina.