There is a "love potion" - some of the versions call it "Honey" instead.
It does the same thing as the love potion on the V4, V4.5 - makes two tamas falling in love and have a baby - but they must be adult characters for it to work.
You can get it with a secret code (keyed in at the shop).
All the codes for the V2 and V3 shops are pinned in our Tamagotchi Codes forum
(the code is different for the V2 vs the V3 so you need to check both topics)