SB 3.5.19

naitac citraṁ tvayi kṣattar
 bādarāyaṇa-vīryaje
gṛhīto ’nanya-bhāvena
 yat tvayā harir īśvaraḥ
Synonyms: 
na — never; etat — such inquiries; citram — very wonderful; tvayi — in you; kṣattaḥ — O Vidura; bādarāyaṇa — of Vyāsadeva; vīrya-je — born from the semen; gṛhītaḥ — accepted; ananya-bhāvena — without deviation from the thought; yat — because; tvayā — by you; hariḥ — the Personality of Godhead; īśvaraḥ — the Lord.
Translation: 
O Vidura, it is not at all wonderful that you have so accepted the Lord without deviation of thought, for you were born from the semen of Vyāsadeva.
Purport: 

The value of great parentage and noble birth is evaluated here in connection with the birth of Vidura. The culture of a human being begins when the father invests his semen in the womb of the mother. According to his status of work, a living entity is placed in a particular father’s semen, and because Vidura was not an ordinary living entity, he was given the chance to be born from the semen of Vyāsa. The birth of a human being is a great science, and therefore reformation of the act of impregnation according to the Vedic ritual called garbhādhāna-saṁskāra is very important for generating good population. The problem is not to check the growth of the population, but to generate good population on the level of Vidura, Vyāsa and Maitreya. There is no need to check the growth of population if the children are born as human beings with all precautions regarding their birth. So-called birth control is not only vicious but also useless.