If there's one subject guaranteed to get the attention of teenagers - and terrify their parents - it's teenage sex.
Ms Pam Stenzel (34) knows this and to 400 transfixed adolescents yesterday morning she proved it. Delivering the same message she has given to more than 250,000 teenagers across the world, she told them sex has a price-tag.
She was at St Mac Dara's Community College in Templeogue, Dublin - the second school she visited yesterday - at the invitation of its headmaster, Mr Seamus McPhillips. The school is co-ed, non-denominational and as full of teenagers and hormones as any.
After a brief introduction, the feisty Minneapolis mother of three got to the point. "My goal is to make sure that you will never have to say again: `I never knew what could happen'.
"God created sex," she proclaimed. "Sex is awesome and God wants you to have great sex." Promising start, many no doubt thought.
"But when sex happens outside boundaries it is horrible. Horrible and destructive. What is the boundary or context in which God created sex?" she asked. "Marriage, that's right.
"God did not create sex for love, He created it for marriage. Sometimes there's love in marriage, too, and that helps."
Part preacher, part comedienne, Ms Stenzel kept the unscripted show for 5th and 6th years going for more than an hour. The message was simple: don't have sex until you're married or suffer the consequences.
And for any who thought pregnancy was the ultimate disaster, she had news.
"There's syphillis, gonorrhea, chlamydia, herpes, genital warts, hepatitis A, hepatitis B, HIV . . ." Thirty STDs were rattled off, along with the "horror" of abortion, the pain of infertility and the ineffectiveness of condoms.
There was little eye-to-eye contact between students during Ms Stenzel's address. A few laughs and a bit of nervous twitching, but overall it was a positive response.
Sarah Doyle (16) said Ms Stenzel "was right about everything - really knows what she was talking about".
A friend (15) agreed that people her age were having sex, adding: "She'd make you think about what you were doing and who with."
Ms Stenzel "really scared" Alan Barry (16) by "talking about all those diseases".
Mr McPhillips felt his American guest had proved herself "the best speaker and educator one could get". Asked whether he thought the numerous references to "God" were out of place in a nondenominational school, his reply was unapologetic.
"Parents are so worried about this issue, they'll put up with a bit of God if the message gets through."