Vestigial structures are organs or structures that once served a purpose in our evolutionary history but no longer serve the same or any purpose.
Examples:
At this stage, the embryo has an overlay of both female and male systems.
Hormones determine the differentiation into either female or male.
True hermaphrodites: Organisms with complete male and female sex organs.
Pseudohermaphrodites: Not true hermaphrodites.
In female embryos exposed to high levels of male sex hormones:
This is a pseudohermaphrodite because they do not have both complete sets of internal organs.
Medical decisions can be made in infancy or later about altering the genitalia.
In minor cases, the clitoris may appear large, resembling a penis, and the vulva may resemble a scrotal sac.
The conditions and their apparent sex based on chromosomal perspective as well as the outcome from those conditions are important to know.
Nondisjunction: Errors in chromosome separation during meiosis, leading to variations in the total number of chromosomes.
Down syndrome and Edward's syndrome are examples of autosomal conditions.
Presence of a Y chromosome determines male sex, regardless of the number of X chromosomes.
Females (variations in X chromosomes):
Males (variations in X chromosomes):
Adding more X chromosomes, whether in females or males, tends to result in a decline in mental cognitive function, though the exact mechanism is unclear. The use of the term "mental retardation" is outdated; "mental cognitive effect" is more appropriate.