The following positions (at the time of intercourse) doubtlessly lead to birth of twins: a) Both Candr and Sukr in even Rasis, or in dual Navamshas (in female Rasis, like Vrishabh, Kark etc., or in Mithun Navamsh and its Kendras); b) Budh in Lagn, while Mangal and Guru are in odd Rasis.

Notes: The first combination can lead to birth of two female issues, as Candr and Sukr are female Grahas. The latter combination is capable of giving two male issues, as Guru and Mangal are masculine Grahas.

Should Lagn and Candr be in even Rasis and receive a Drishti from a strong Grah, then there are twins in the womb (one female and one male). Similar results follow, if Candr and Sukr are in even Rasis, while Guru, Mangal, Budh and Lagn are posited in odd Rasis, or in dual Rasis and are with strength, (Slokas 21 and 22, Ch. 8 of Saravali, my English translation) Incidentally, from the said Ch., we see below the combinations of Grahas for birth of triplets: The following Yogas prevailing at the time of Adhana lead to birth of triplets: a) Budh remaining in Mithun Navamsh giving a Drishti to a Grah, who also falls in a dual Navamsh; b) Budh remaining in Mithun Navamsh giving a Drishti to a dual Rasi, which ascends; c) Budh in Kanya Navamsh giving a Drishti to a Grah falling in dual Navamsh; d) Budh in Kanya Navamsh giving a Drishti to a dual Rasi, which ascends. e) Budh in Mithun Amsh giving a Drishti to a Grah in Mithun Amsh, or Dhanu Amsh; f) Budh in Mithun Navamsh giving a Drishti to Lagn, which falls in Mithun Navamsh, or in Dhanu Navamsh; g) Budh in Yuvati Bhava giving a Drishti to a Grah in Kanya/Meen Navamsh, or giving a Drishti to such Lagn Navamsh.