What is that of a man which has four constituents (mahabhutas) and six sources (rasa) and which comes out of him while he cohabits with a woman of a different clan in a lonely place after her menstrual cycle and is converted into embryo in the woman?
The wise call it shukra, that which is implanted for the conception of an embryo. It is made up of four elements-vayu, agni, prithvi and apa (four mahabhutas) which contribute one fourth of the attributes of each of the mahabhuta and is originated from six rasas.
सम्पूर्णदेहः समये सुखं च गर्भः कथं केन च जायते स्त्री| गर्भं चिराद्विन्दति सप्रजाऽपि भूत्वाऽथवा नश्यति केन गर्भः ||५||
How and with what factors does the fully developed fetus get delivered in time and with ease? How does even a fertile woman face delay in conception? Why sometimes does the embryo get destroyed?