《论衡·卷二·命义篇》
《月令》上说： 这个月一一夏历二月，要开始打雷，有同房行为不谨慎的，生下来的子女形体就会有缺陷，而且肯定要有大的灾祸。 
《月令》曰： 是月也，雷将发声。 有不戒其容者，生子不备，必有大凶，喑聋跛盲。
"Monthly Order" says: This month - the second month of the Chinese calendar - should start with thunder, and those who have an incautious sex life will have children with physical defects, and will definitely have a major disaster.