On the V1, V2 and V3 Connections/Connexions the only time you get twins is when the female tama gives birth to two babies of the same sex and one immediately leaves the screen to join the male tama.
There is no 'cheat' or 'code' to get twins on IR ConneXions / ConneCTions.
This is something that has also been confirmed by BanDai.
It doesn't matter which one you have heard, nor if it is one that sounds like it could work - I promise you that it is a rumour that surfaces on a tediously regular basis - appprox once every 2 weeks! (...and it is not true... )
Have a look at this web page (originally posted by OsuMesu21) - twins rumour history!
No one who has posted a picture on TamaTalk has ever been able to give detailed, credible information on how the babies / toddlers / teens live together on the screen - how they are fed, go on the potty, play games, etc....
The only twins on screen at the same time that we know about are the character(s) on the AngelGotchi "Futago-tenshi" - otherwise, they don't exist