I know for some this is a contentious issue and you may not want to discuss this with a child. But just like you expect respect for your family dynamics and individual life so do others. Here are some great books that open a dialogue around the LGBTQ (lesbian, gay, bisexual, transgender and queer/questioning) community and families.
Toddler to early elementary: Morris Micklewhite and the Tangerine Dress by Christine Baldacchino is about a boy who loves to wear a tangerine dress at the play center because it reminds him of his mother's red hair and lions. He is teased for wearing a dress but soon he decides it doesn't matter as long as he is happy. This was a great conversation starter with my 5 year old about gender stereotypes.
Middle Grade: Drama by Raina Telgemeier, a great coming of age graphic novel. All the typical trappings that face pre teens that include a gay and questioning teen.
Beyond Magenta: Transgender Teens Speak by Susan Kuklin are transgender teens in transition, have transition are questioning. An honest account of what it is like being a teen who is changing into their gender preference. And great photographs that goes with these stories.