Mahabharata 12.285.11

यत्र तत्र कथं जाताः स्वयोनिं मुनयो गताःशूद्रयोनौ समुत्पन्ना वियोनौ च तथापरे

yatra tatra kathaṃ jātāḥ svayoniṃ munayo gatāḥśūdrayonau samutpannā viyonau ca tathāpare

Our plain-language meaning of this verse is waiting for scholar review.