6:42  

अथवा योगिनामेव कुले भवति धीमताम् ।
एतद्धि दुर्लभतरं लोके जन्म यदीदृशम् ॥६- ४२॥

athawaa yoginaamewa kule bhawati dhiimataam ।

etaddhi durlabhataraM loke janma yadiidRRisham ॥६- ४२॥

Source: Automatic ITRANS Transliteration

Otherwise, born into a family of wise yogis,
A birth like this is very difficult to obtain in this world.

Source: Milind S. Pandit

Such a yogi is born in a family of wise transcendentalists. A birth like this is very difficult, indeed, to obtain in this world.

Source: The Bhagavad-Gita: The Sacred Song

Or he takes his birth in a family of transcendentalists who are surely great in wisdom. Verily, such a birth is rare in this world.

Source: Bhagavad Gita As It Is