Srimad-Bhagavatam: Canto 3 - Chapter 1 - Verse 35


तावेव ह्यधुना प्राप्तौ पार्षदप्रवरौ हरे: ।दितेर्जठरनिर्विष्टं काश्यपं तेज उल्बणम् ॥ ३५ ॥


tāv eva hy adhunā prāptaupārṣada-pravarau hareḥditer jaṭhara-nirviṣṭaṁkāśyapaṁ teja ulbaṇam


Lord Brahmā continued: Those two principal doorkeepers of the Personality of Godhead have now entered the womb of Diti, the powerful semen of Kaśyapa Muni having covered them.


Here is clear proof of how a living entity coming originally from Vaikuṇṭhaloka is encaged in material elements. The living entity takes shelter within the semen of a father, which is injected within the womb of a mother, and with the help of the mother’s emulsified ovum the living entity grows a particular type of a body. In this connection it is to be remembered that the mind of Kaśyapa Muni was not in order when he conceived the two sons, Hiraṇyākṣa and Hiraṇyakaśipu. Therefore the semen he discharged was simultaneously extremely powerful and mixed with the quality of anger. It is to be concluded that while conceiving a child one’s mind must be very sober and devotional. For this purpose the garbhādhāna-saṁskāra is recommended in the Vedic scriptures. If the mind of the father is not sober, the semen discharged will not be very good. Thus the living entity, wrapped in the matter produced from the father and mother, will be demoniac like Hiraṇyākṣa and Hiraṇyakaśipu. The conditions of conception are to be carefully studied. This is a very great science.