I've been searching for just the right book for my 11 year old son and this is one has just the right look and information I wanted for him. Many other books were way too long, some with pages in the hundreds and other books were too immature for his age. This is a great beginner book for covering all of the facts and terms. An 8 yr. old would need help reading it but an 11 yr. old could read it alone. I think it would be fine even for 12-13 who hasn't learned much about reproduction and puberty. The illustrations are simple but accurate, not like some I've seen that are more like from a medical textbook or cartoonish. There is a glossary with pronunciations and definitions. I like that it is Christian and family based. It's everything I was looking for!!