Here is an example the way I analyze horoscopes. Yesterday, I analyzed a horoscope from 1963/64.
1. "Santati Karak" planet Guru in Meen raashi and in Meen Navamansh. Meen raashi is DWI-Swabhav raashi and meen navamansh in it is last 3 degree 10 minutes which takes the dwiswabhav part to a higher degree. So, possibility of "twins" is there in the "root" form in the horoscope. But Guru stays in one raashi for 12 months and in 1 navamansh for 1.3+ months. So all folks born in this period would have this formation.
2. Now, in this Dhanu lagna horosocpe, Mesh was in the sign in the 5th house (Santati sthan). The owner of the Mesh sign i.e. santati sthan in this horoscope -- MANGAL-- was in Kumbh raashi and surprise -- again in Meen navamansh in Kumbh raashi!! So additional effect. Mangal changes sign in aprx 45 days and 1 navamansh in aprx 6 days. The Dhanu lagna was only for 2 hrs each day in those 6 days! So this narrows down the tme period quite a bit.
3. BUT, Mangal is also with Shani although not very close -- This shows that there could be some issues wth at least 1st Santati.
4.a Mangal is "Bhratru-Karak" i.e. "sibling-karak" (for everyone)-- It is in the 3rd house in the horoscope - 3rd house is also of Siblings (apart from other things). So it being with Shani either shows pregnancy issues to his mother after his birth OR some longevity/accidental issues with his next brother related to legs.
4.b Shani being the owner of the 3rd house (Kumbh raashi) ONLY adds to these effects of 4a as both bhratru-karak and sibling house owner are together in 3rd house which is of siblings.
5. The biggest Santati decision making factor is that Guru is 5th from Moon (Vrushchik) and also owner of 5th house from moon. (5th house is Santati sthan) This seals the deal as they say.
1. Yes, the 1st pregnancy for him was twins but it turned to be a mis-carriage.
2. His younger bro passed away in aprx 10 years back.
3. I did not check about a miscarriage etc to mother with him.
This example shows or illustrates what is meant by Guru being Santati-Karak, Mangal being Bhratru-Karak and also aspects about or effects of Shani-Mangal yuti in the horoscope especially when they are the owner of 3rd house.
I have a separate post for HIGH number of TWINS born in Feb 1975 to Mar 1976 and also quite a few folks born in this period have been blessed with twins. (Guru was in Meen raashi in this period & was wakri in Meen navamansh increasing the period of Guru being in Meen navamansh!) : http://astromnc.blogspot.com/2009/03/twins.html