Wildcards

[nite train 919]

I've found that if you collect all the hearts without dying on the 7th breeding mini game you will always get a wildcard. Only in random events will you get a twin bonus wildcard.

[sleepyowl]

See the already existing threads on wild cards. It is true that the flashing heart stage of the romance game nets you a wild card. The twins, however, are gained through getting through the maze with the required (not necessarily all) number of hearts very quickly.
If you can collect them all very quickly, you get twin wild cards.

[Big_Sama]

Yeah it's not random, most of the time for me atleast if you finish with 15+ seconds left you get twins and wildcards

[sleepyowl]

I'd say with 10-15 seconds left. I've had some that gave it to me with less than. It really varies between species. As a general rule though 15 s would most certainly get it.