大般涅槃經義記 9.199

9.199

第二謗無父母之中有六復次：初直設難，若言父母是眾生因則應常生，以不常生，明知父母非眾生因。二若言父母是眾生因，因無缺少，所生之子一人應具男女二根；然無具者，明知非因。三眼見眾生不似父母，明知非因。四眾生父母同於四無，明知非因。先舉四無，次明父母同彼四無，下就設難，若言是因，父母死時子不必死，明知非因。五有化生及濕生等，明知父母非眾生因。六舉諸鳥得身各異，明知非因。

In the second, slandering that there are no father and mother, there are six points: First, directly raising a challenge: if it is said that father and mother are the cause of sentient beings, then they should constantly give birth; since they do not constantly give birth, one clearly knows that father and mother are not the cause of sentient beings. Second, if it is said that father and mother are the cause of sentient beings, the cause being without deficiency, the child born should possess both male and female faculties in a single person; yet as none possesses both, one clearly knows they are not the cause. Third, one visually sees that sentient beings do not resemble their father and mother; thus one clearly knows they are not the cause. Fourth, the father and mother of sentient beings are identical to the four non-existents; thus one clearly knows they are not the cause. First it cites the four non-existents, next explains that father and mother are identical to those four non-existents, and below raises a challenge: if they are said to be the cause, then when the father and mother die, the child does not necessarily die; thus one clearly knows they are not the cause. Fifth, there are apparitional births, moisture-born births, and so forth; thus one clearly knows father and mother are not the cause of sentient beings. Sixth, citing that various birds obtain different bodies; thus one clearly knows they are not the cause.