S.E.X.: The All-You-Need-to-Know Progressive Sexuality Guide to Get You Through High School and College A great resource for your teens (and you) when they are ready to find reliable answers for themselves.
The New Speaking of Sex: What Your Children Need to Know and When They Need to Know It Everything is in this book. A great resource for 15-25 year olds.
On Your Mark, Get Set, Grow!: A "What's Happening to My Body?" Book for Younger Boys A starter book for parents.
It's So Amazing!: A Book about Eggs, Sperm, Birth, Babies, and Families Madaras is the go-to author for young people on puberty.