The Gorham Middle School principal is apologizing for a presentation during the school’s diversity day that turned sexual in nature. A group called Proud Rainbow Youth of Southern Maine gave a presentation last month about gender diversity and discrimination. Parent Kristy Howard told WCSH-TV that a teacher should have stepped in when the topic turned to sexual foreplay during a question-and-answer session. She said she was shocked when her son told her about it. Principal Robert Riley said he was alerted by some teachers who said it happened so fast they did not know how to respond.