Recognition of LGBT rights has come a long way in recent years, with first civil partnerships and then marriage equality. But there are still some strides to make, despite resistance from certain groups, to achieve real equality and acceptance of the diverse nature of human sexuality and gender identity.
The concern for equality and genesis of this project stems not from identifying as LGBTQ myself but rather from my humanist beliefs. Bad ideologies and handed-down concepts from religion would have you believe that we have been made in a clearly defined, binary way, but this could not be further from the evidence.
The variation in gender and sexual identity is vast, which is why we see the LGBT term being extended to LGBTQ, LGBTI, and LGBTQ+.
There is not room here to expand on all the possibilities that the + encompasses, so I will instead recommend you look at the work of Dr. Veronica Drantz and her explanation of how genetics and hormones affect our identities.