Having a baby, boy or girl

So was wondering if anyone know how accurate this is? I got one sims alien pregnant and he ate so much carrot he could not eat anything else. He also listened to alternative on the radio a lot and still he had a girl. So I was thinking if it doesn't really work on aliens or its not that accurate in the first place as I didn't get a boy. Anyone else had this happen?/ Know how much you should eat and listen?