Narada Purana (Jyotisha Selections) · by Vyasa
Chapter 2 · Signs, Planets, Birth
जातकम् १
चतुष्पदर्क्षगे भानौ शेषैर्बलयुतैः खगैः ।कोशादतौ तु यमलौ जायेते मुनिसत्तम ॥ ७१ ॥
In the full Narada Purana (Purva Bhaga) this is chapter 55, verse 71.
The Sun may be in a four-footed sign, with the other planets strong. Then twins are born wrapped in a sac, O best of sages. (Our text is unclear here: the word read as 'wrapped in a sac' is damaged.)
Simple meaning: The Sun in a four-footed sign with strong planets can give twins in one sac.
सार्क्यारसिंहोज्ञाजांसे भांशतुत्यांगनालयुक् ।
A lagna in Leo, Taurus or Aries navamsha with Saturn or Mars can mean the cord wraps a limb.
सपापगोऽर्को जायो वा परवीर्यप्रसूतिकृत् ।
With these placements, the verse says the child may be from another man.
विदेशगः पितावृद्धः खेवा राशिवशात्यये ।
The father may be away or old. A full Moon in its own sign starts a rule for the place of birth.