Police are investigating allegations that a 13-year-old boy blackmailed as many as six girls into performing sex acts. Jeff R. Temple, an associate professor at UTMB and author of multiple studies on sexting, urged parents to share this cautionary tale with their children. “Use this as a learning opportunity,” said Temple, who has researched the prevalence of sexting among high school students. He said teenagers — particularly girls — should understand they never have to submit to such “sextortion.”