Knowing the preceptor's wife at the preceptor's behest, does not stain the pupil. The sage Uddalaka caused his son Shvetaketu to be begotten by a disciple.
गुरुतल्पं हि गुर्वर्थं न दूषयति मानवम्। उद्दालक: श्वेतकेतुं जनयामास शिष्यतः॥