父母应该和孩子进行开放的性话题对话，帮助他们建立正确的观念。

Parents should have open ___sex-talk with their children to help them develop healthy attitudes.

他们的谈话逐渐从随意话题转向了带有挑逗意味的性话题。

Their conversation gradually shifted from casual topics to playful ___sex-talk.

学校安排了专门的课程来进行性教育讨论。

The school has scheduled special classes for ___sex education.