As a doctor, specialising in the field of gender variance, I hear stories from patients every day that lead me to question the difference between our biological sex and the corresponding gender assigned to us at birth. Often the two are the same, but this is not always the case.
Contrary to popular belief, transgender people weren't born in the wrong body, they weren't misgendered, they don't want to change sex, they haven't got some altered ego - they, like everyone else, were born with a gender that was set at conception. However, this gender was different to the one with which they were labelled at birth.
In the very same way that being born with a penis doesn't automatically mean you are attracted to women: just because you are born with testicles, doesn't mean your gender is male. Your biological sex is either male or female, but your gender may be one or the other - or anything on the spectrum between the two.
In order to better understand this, we need to consider biological sex and gender as two independent elements.
As a general rule, we are assigned a 'biological sex' by our chromosomes. Each of our mother's eggs carries an X chromosome and then the sperm from our father carries either an X or a Y chromosome. If an X sperm fertilises the egg then you get an XX picture, which creates female reproductive organs (womb, ovaries, fallopian tubes). If a Y sperm gets to the egg first, then you get an XY picture, and male reproductive organs develop (testes, prostate, penis).
This is our biological sex, and it is the ovaries - or the testes - that produce the relevant hormones to develop our secondary sex characteristics, when we reach puberty.
Gender, on the other hand is assigned by society. At the point where the midwife looks at our genitals and tells everyone whether it's a 'girl' or a 'boy', our society partitions us into 'male' or 'female'. This assigned gender dictates, to a greater or lesser degree, what clothes we wear, what toilet we use, what toys to play with and what job and role in life we might aim for.
Unlike homosexuality, gender variance needs a little bit of medical help to allow the person to achieve the characteristics that fit their true gender.
If a patient's gender is male, medical intervention can help to prevent them from growing breasts and hips, if female, they can prevent the patient's voice from breaking and their muscles and bones developing into large, out-of proportion reminders that their biological sex doesn't match their gender. Such steps to help patients achieve their true gender can actually be lifesaving. In fact, in the UK alone, it is believed that half of transgender people have thought about self harm and suicide.
Because they are in the minority and there is a lack of understanding about their situation, many transgender people do not feel able to reveal their true selves to society. Many of my patients tell me that they have lived a lie their entire life, simply coming to terms with their situation.
Who among us, when looking in the mirror, hasn't felt a pang of regret that the image they see isn't quite what they might hope for? We may feel disappointed by our ageing bodies, but what if the person you saw staring back at you was entirely different to how you truly saw yourself - someone else altogether?
As a society we have come to understand that biological sex is very different to sexual orientation, in fact to suggest that they are one and the same thing would be laughable. Gender is no different. What we are as individuals is far more complex than a simple tick in a box marked: male or female.