There’s a lot more than your sex being assigned at birth as male, female, or any other gender. Your biological or assigned sex does not always tell your full story.
While most people are born prepared to feel comfortable with their assigned sex and are attracted to the opposite sex upon sexual maturity; there are quite a few people who do not fit into this mould. Homosexual people are attracted to same-sex people. Transgender individuals feel that they belong to the opposite sex wearing the wrong body type.
It is common for people to confuse sex, gender, sexual orientation, and gender identity, but they are different.
Sex is a label that a doctor assigns to an individual at birth (male or female) according to their genitals and chromosome. Which apparently goes in your birth certificate.
Gender is a much more complex term. Each culture/society has a set of expectations of how a particular gender should behave. A presumptive set of characteristics, behaviours, and thoughts interlinked with gender, but instead of being about body parts, it's about how you’re expected to act.
Sexual Orientation is whom you’re attracted to emotionally, physically, and mentally and with whom you want to build a relationship.
Gender Identity isn’t about whom you’re attracted to but who you ARE. It means how you feel inside about your gender and how you wish to express it through various ways (clothing, behaviour, appearances, etc.)
There is widespread prejudice against homosexual and transgender individuals and consequently, they have difficulties or are not comfortable expressing themselves and exploring their options freely in their early teens. Peer pressure, culture, and the fear of being different from others can cause teens to question themselves in many areas.
Individuals who are lesbian, gay, bisexual, or transgender sometimes don't reveal their sexual orientation or gender identity for a long time. Even after an individual identifies their sexual orientation and gender identity the main problem they face is support from the people they love or because they have been ridiculed, rejected, or harassed.