Human gender is decided at conception.
But the gender isn't physically apparent until after 7/8 weeks. From this point the embryo develops easily identifiable gender features. But before this time the embryo/zygote appear neutral and it is a misconception that these neutral embryo/zygote are female. Though the only way to tell gender at this stage would be a genetic test.
---
They don't necessariy start as female, but they do have female organs. It is the presence of chemicals (due to Y chromosome) that forms the male organs from the female organs later on.
All mammals technically are neither female nor male when starting out, although some people would say that lack of genitalia would categorize as female. Hormones that decide gender come into play later in the fetus's development.
we do not start out female in the womb, the gender of a child is immediately determined at conception, meaning as soon as a sperm cell bonds with an ovum(or egg) our gender is determined because sperm contain both X and Y chromosomes, while female ova only contain X chromosomes, which means that sperm ultimately determines the gender of a child(if an X chromosome carrying sperm cell bonds with an egg, the child will be female cuz XX chromosome pair creates a female but if a Y chromosome carrying sperm cell bonds with an egg, the child will be male because XY chromosome pair creates a male, and there are exceptions to this that result in genetic anomalies, such as women being born with an XY pair and vice versa)
the reason why people believe that humans start out female in the womb is because for a time, the child's genitalia remains undistinguishable until certain hormonal procresses form them and thus they pair the absence of any distinct genitalia with being female
and in fact, both males and females originate with the same genitalic tissues until the above mentioned hormones produce their respective genitalia(this is how certain male and female genital parts are homogolous, because the tissues that create the certain genital parts in males, will create the equivalent parts in females, and vice versa i.e. the clitoris and penis - the tissue that creates the penis if the child is male(determined from conception), will create the clitoris if the child female(determined from conception), labia majora + minora and scrotum - the tissue that creates the scrotum if the child is male, will create the labia majora and minora if the child is female)
so if the child is determined to be male from conception, then it will continue growing as a male and remain without any distinguisable genitalia until a hormone known as SRY(which a child can only have if its determined to be male at conception ) stimulates the growth of the penis, scrotum, testicles, etc. If its female, then it will continue growing as a female and remain without distinguishable genitalia until hormones stimulate the growth of the vagina, labia, clitoris, etc.
so for the last time, a child's gender is determined at conception, immediately as the sperm bonds with the egg and no matter what gender it is, it will remain without any noticeable genitalia(merely genitalic tissues) until certain hormones create them(so a male fetus without any distinct genitals isn't female, its just a male who is in the procress of developikng and just hasn't developed genitals yet)
Embryos can be male or female.
Two thing embryos need are nutrients and protection
The embryo develops not in the wombYour species may vary. Mammalian embryos develop within the uterus of their mothers. Bird and reptile embryos develop inside eggs. Some oviparous embryos develop inside eggs inside their mothers. In some fish and seahorses, the eggs laid by the female, but carried by the males in a pouch and the embryos develop within him.
vagina
My understanding of this begins with the formation in utero of the embryo. All human embryos start out bipotential which means that embryos have the potential to become either sex. As a female will have an endocrine system that will eventually consist of breasts, men too have the same endocrine system. But the hormones in the male will stop male breast tissue from growing into milk-producing breasts. In short, men have nipples because they are the same essential creatures as females. What parts grow into what is determined by chromosomes, genes and sex hormones.
No, not all organisms start out as embryos. Embryos are typically seen in higher animals that undergo sexual reproduction, where a fertilized egg develops into an organism. Organisms like bacteria and protists reproduce asexually and do not have an embryonic stage in their life cycle.
Actually all embryos start out as female and develop male genitalia fairly late.
the sex of all embryos is decided when the sperm meets the egg. The egg is x and the sperm is either x or y. If y then it is a male and x is female.
Embryos can be male or female.
Placentals
All embryos must have a mechanism for absorbing oxygen
All chordates embryos have pharngeal slits.
the 2 things that ALL growing embryos need are food and oxygen
The female reproductive system nurtures and protects developing embryos. The circulatory and endocrine systems also have a role in this nurture and protection.
The early embryos of all animals have a very similar appearance. This is no different for chicken and pig embryos.
Two thing embryos need are nutrients and protection
All vertebrate embryos look roughly the same, showing that they come from a common ancestor.