Gender is not just a column in an application form to check like a multiple-choice question, it is way more than that. There's history, mythology, and most importantly biology involved in it. But typically people stuck up with the concept of the gender binary and believe genders other than male and female, are abnormal, unacceptable, unethical, and impractical. Apart from knowing about the penis and vagina, there are a few more important things a person needs to know.
Generally, gender identities revolve around a person's genitals and that's how medically and biologically, any infant can get recognized as a male or a female and not any other gender identity, especially during birth because one can't feel the identification crisis or sexual emotions or intimate feelings of a newborn child. Hence, people conclude a kid's gender identity by looking at one's genitals. A penis with testicles makes that kid a male, and a vagina makes that kid a female. Well, this is the most common and basic procedure of recognizing a person's gender identity.
There is a huge exception with identifying the gender of a kid during birth, and this can be seen in the cases of Intersex children. Intersexuality is a gender identity rather than a typical sexual orientation. This has to do everything with the hormonal imbalance, chromosome shuffling, and blended external genitalia. This is proper biology and it is mo