Loss of Virginity
20 Boy Summer - Sarah Ockler
A Bad Boy Can Be Good for a Girl by Stone
Amelia O'Donohue is SO not a virgin - Helen FitzGerald (in this case, the main character forgets she lost her virginity)
Anatomy of a Boyfriend by Snadowsky
Annie on My Mind by Garden
Before I Die by Downham
Boy Toy by Barry Lyga (student-teacher relationship)
Boyfriends with Girlfriends by Sanchez
Breaking Up is Hard to Do: Stories about falling out of love by Four Incredible Authors
Bumped by Megan McCafferty (dystopian)
Crazy" by Benjamin Lebert.
Doing It by Melvin Burgess
Don't Let Me Go by Trumble is LBTQ and has first sexual experiences.
Forbidden by Tabitha Suzuma (brother-sister relationship)
Forever by Judy Blume
Girl Wonder by Alexa Martin (girl perspective)
Good Girls by Ruby
Had Seen Castles by Cynthia Rylant where the male main character loses his virginity before going off to war. He gets distracted by the thought of spaghetti... :)
Just Friends by Norma Klein (good friends decide to lose virginity to each other)
Little Brother by Cory Doctorow
Looking for Alaska & The Fault in our Stars by John Green (one from male, one from female perspective)
Lost It by Tracy
My Life Next Door - Huntley Fitzpatrick
Pop! by Wallington
Prep by Curtis Sittenfeld
Pure by Rebbecca Ray (girl perspective)
PURGE by Katie Spofford loss of virginity & feelings around it is the trigger for a suicide attempt that finally puts the MC in treatment for her bulimia.
Purity by Jackson Pearce
Rainbow Boys by Sanchez
Rampant - Diana Peterfreund (one of the characters is date-raped, if I remember correctly. Plus, virginity is key to protection against killer unicorns)
Rats Saw God by Thomas
Ready or Not by Meg Cabot
Shut Out by Kody Keplinger.
Sisterhood of the Traveling Pants by Brashares
Slam by Nick Hornby
Soul Thief, by Jana Oliver (human girl, paranormal male)
Speak by Laurie Halse Anderson
Story of a Girl by Zarr
Ten Things We Did (And Probably Shouldn't Have) by Sarah Mlynowski
The Fault in Our Stars by John Green - which includes a great Venn Diagram about virginity loss.
The Lucky Kind by Alyssa B. Sheinmel for an interesting boy perspective.
The Mockingbirds - Daisy Whitney
The V Club by Brian
Trafficked by Kim Purcell
Tricks by Ellen Hopkins
Unexpected Development by Perez
What I Did't Say by Keary Taylor (boy perspective)
Why We Broke Up, by Daniel Handler