The sex of an individual is determined by their genetic makeup. Females have two X chromosomes (XX) while males have one X and one Y chromosome (XY).
Yes, it is possible for someone to have a combination of male and female sex characteristics. This is known as intersex or disorders of sex development (DSD). It occurs when there is a discrepancy between a person's genetic sex and their physical sex characteristics.
Yes, a person's gender identity can differ from their biological sex. Gender identity is a person's internal sense of being male, female, or another gender. It is not determined by biological factors, but rather by an individual's personal understanding and experience of their gender.
Methods for determining sex, such as ultrasound or DNA testing, are generally very accurate. However, there is always a margin of error and these methods may not always be able to detect intersex conditions or other variations in sex characteristics.
While a person's biological sex cannot be changed, their gender identity can. Some individuals may undergo gender confirmation surgery or hormone therapy to align their physical appearance with their gender identity. However, this does not change their biological sex.