SB 6.1.24

tasya pravayasaḥ putrā
 daśa teṣāṁ tu yo ’vamaḥ
bālo nārāyaṇo nāmnā
 pitroś ca dayito bhṛśam
Synonyms: 
tasya — of him (Ajāmila); pravayasaḥ — who was very old; putrāḥ — sons; daśa — ten; teṣām — of all of them; tu — but; yaḥ — the one who; avamaḥ — the youngest; bālaḥ — child; nārāyaṇaḥ — Nārāyaṇa; nāmnā — by name; pitroḥ — of the father and mother; ca — and; dayitaḥ — dear; bhṛśam — very.
Translation: 
That old man Ajāmila had ten sons, of whom the youngest was a baby named Nārāyaṇa. Since Nārāyaṇa was the youngest of all the sons, he was naturally very dear to both his father and his mother.
Purport: 

The word pravayasaḥ indicates Ajāmila’s sinfulness because although he was eighty-eight years old, he had a very young child. According to Vedic culture, one should leave home as soon as he has reached fifty years of age; one should not live at home and go on producing children. Sex life is allowed for twenty-five years, between the ages of twenty-five and forty-five or, at the most, fifty. After that one should give up the habit of sex life and leave home as a vānaprastha and then properly take sannyāsa. Ajāmila, however, because of his association with a prostitute, lost all brahminical culture and became most sinful, even in his so-called household life.