The main curricula we use are from the series "Our Whole Lives, Sexuality Education" (OWL) based on national Guidelines for Comprehensive Sexuality Education set by the Sexuality Information and Education Council of the United States (SIECUS), and have been taught to great acclaim all over the country since the year 2000. Although OWL is jointly published by the Unitarian Universalist Association and the United Church of Christ it is important to know that this curricula is entirely secular, and contains no religious dogma, making it entirely appropriate for use in any school or community setting.
There are age appropriate courses for different grade levels. The 7-9th grade junior high program, which we use the most, published its 2nd edition in 2014, after field testing it around the country for about a year; it's very up-to-date.
The 7-9 grade "Our Whole Lives" curriculum is the longest, with twenty five 90-minute sessions, so if the group meets once a week, that’s about a six-month-long class.
Some people may react, “how much sex ed can middle schoolers possibly need?” but let’s point out again that it’s MORE THAN sex ed, it’s about establishing lifelong SEXUAL HEALTH, and the answer is a lot!