You abstain – and you gain. This ascetic principle has long been preached by many religious leaders, medical doctors and others. It could be abstaining from pre-marital sex or practising celibacy, fasting during Lent or Ramadan, or not smoking or drinking alcohol. The gain is typically spiritual growth or better health. Sometimes it becomes a public campaign, such as Stoptober, the quit-smoking month of October, or Veganuary, a January push to get people to abstain from eating or using animal products. At the same time, interest in the so-called 4B movement to boycott heterosexual relations wi…