Transgenderism is the practice of transgressing gender norms.

Transgender folks come in several flavours:

• FTM (female to male) are people who were born female but see themselves as partly to fully masculine.
• MTF (male to female) are people who were born male but see themselves as partly to fully feminine.

• Intersexed are those born with some combination of male and female physiology, who may accept as natural their mixed gender.

Gender variations are more common that most people suspect, because many people hide their true nature out of fear for their safety and security. Many people explore gender behaviour without identifying themselves as transgendered. Women wearing pants may not seem transgender today, but fifty years ago it would have been. Boys wearing "girls clothes" might not see themselves as inherently feminine, yet enjoy playing in this way. While crossdressing is enjoyed by both males and females, it appears to be more pronounced in males because of an imbalance in norms of attire and attitude (we see less transgression when a woman wears a suit).

In order to understand the difference between someone who is gay, lesbian or bisexual, and someone who is transgender, you need to be clear on the distinction between sex and gender.

Simplistically, sex is polarity of anatomy, gender is polarity of appearance and behaviour. As one becomes more closely involved with transgenderism, these definitions quickly break down, but they serve as a good starting point.