Narada Purana (Jyotisha Selections) · by Vyasa
Chapter 2 · Signs, Planets, Birth
जातकम् १
लग्नेंदुसमगौ युग्मस्थाने वा यमलंकराः ।ग्रहोदयस्थान्द्यंगांशान्पश्यति ज्ञे स्वभागगे ॥ ५६ ॥
In the full Narada Purana (Purva Bhaga) this is chapter 55, verse 56.
Or the lagna (rising sign) and the Moon are in even signs or even places. These make twins. Mercury may be in its own navamsha (one-ninth part of a sign). It sees the planets and the lagna in dual-sign navamsha.
Simple meaning: The lagna and the Moon in even signs can give twins.
त्रितयं ज्ञांशकाद्युग्मममिश्रैः सममादिशेत् ।
Mercury's sight can give three at one birth. A lagna late in Sagittarius begins a rule for many.
वीर्याढ्यज्ञार्किसदृष्टैः कोशस्थावहवोगिनः ।
Strong Mercury and Saturn can give many in one birth. The ten womb months each have a planet lord.
मासानां तत्समं वाच्यं गर्भस्थस्य शुभाशुभम् ।
Each month of pregnancy goes well or badly by its lord. Mercury in a luck house can bring a deformed child.