I can't really think of a scientific basis for this theory Although having a boy is more likely (I think) in the early part of the fertile period .. so maybe a more dominant female is more likely to say "let's get it on" or something? (Clearly second time around any female is more likely to say "I'm just going to lie here, you do what you can" at any point in her cycle )
I think this theory's crap as well - my eldest is a girl and I'm definitely the boss, no matter what dh says
For what it's worth I have 3 dds and 1ds - all the girls were (happy )'accidents' but my son was planned - don't know if there's a theory there or not.
expatinscotland - say what ya think girl. Starshaker LOL at comments. I believe in the XX and XY theory, but after reading all of your comments I'm moving slightly to perhaps if the female is the trouser wearer then the first born is a girl.