Jatakaparijata 13.24

13.24

atha thamalādijanikarā yogāḥ |
yugme candrasitau tathaujabhavane syurjñārajīvodayāḥ lagnendū nṛnarīkṣitau ca samagau yugmeṣu vā prāṇinaḥ |
kuryuste mithunaṃ gṛhodayagatāndvyaṃgāṃśakānpaśyati svāṃśe jñe tritayaṃ jñagāṃśakavaśādyugmaṃ tvamiścaiḥ samam ||

Now, the yogas causing the birth of twins and multiple births:
If the Moon and Venus are in an even sign and the ascendant, Mercury, Mars, and Jupiter are in an odd house, or the ascendant and the Moon are aspected by a male planet and in an even sign, or the creatures are in dual signs;
they would cause twins; when Mercury in his own navāṃśa aspects the dual navāṃśas that have reached the rising house, triplets arise; through navāṃśas of Mercury, twins are produced equal to the divisions.