SB 3.21.1

vidura uvāca
svāyambhuvasya ca manor
 vaṁśaḥ parama-sammataḥ
kathyatāṁ bhagavan yatra
 maithunenaidhire prajāḥ
Synonyms: 
viduraḥ uvāca — Vidura said; svāyambhuvasya — of Svāyambhuva; ca — and; manoḥ — of Manu; vaṁśaḥ — the dynasty; parama — most; sammataḥ — esteemed; kathyatām — kindly describe; bhagavan — O worshipful sage; yatra — in which; maithunena — through sexual intercourse; edhire — multiplied; prajāḥ — the progeny.
Translation: 
Vidura said: The line of Svāyambhuva Manu was most esteemed. O worshipful sage, I beg you: Give me an account of this race, whose progeny multiplied through sexual intercourse.
Purport: 

Regulated sex life to generate good population is worth accepting. Actually, Vidura was not interested in hearing the history of persons who merely engaged in sex life, but he was interested in the progeny of Svāyambhuva Manu because in that dynasty good devotee kings appeared who protected their subjects very carefully with spiritual knowledge. By hearing the history of their activities, therefore, one becomes more enlightened. An important word used in this connection is parama-sammataḥ, which indicates that the progeny created by Svāyambhuva Manu and his sons was approved of by great authorities. In other words, sex life for creating exemplary population is acceptable to all sages and authorities of Vedic scripture.