She was quite upset and refused the assignment. She didn't think she would actually be able to talk about the subject. Eventually, she changed her mind as the alternative was to be fired. 

On the first day of school she drew a woman's body on the blackboard, pointed to the chest and asked the class "Does anyone know what this is called?" 

Jane, who was sitting in the first row, raised her hand and answered "It's called a 'breast' and my mommy has two of them!" 

"Very good," said the teacher. Then she drew a male body on the board, pointed to the groin, and asked "Does anyone know what this is called?" 

This time Billy raised his hand. "I know what it is! It's called a 'penis' and my daddy has two of them." 

"That's the right name," said the teacher, but I don't think your daddy has two of them." 

"Yes he does!" said Billy. "He has a little one that he uses to pee, and big one he brushes mommy's teeth with!"