Sorry, but the twins method didn't work out in my experiment.. I still believe the twins are random.

No twins at all throughout the experiment, just single babies.. I tried:

• Cologne on wife, Perfume on husband, boost on husband
• Perfume on wife, Cologne on husband, boost on wife
• Cologne on wife, Perfume on husband, boost on wife
• Perfume on wife, Cologne on husband, boost on husband

I did this with a fresh family and used backups to undo the child they had to use the 4 different methods I listed. I think you're just lucky with the multiples! Congrats on your good fortune, cindy!