Yes, this could be just another idea in the long list of ways that you can try to determine the sex of your baby, honestly, I don't know of the other ideas (please share them with us by making a comment below if you know of any!) and I hadn't thought much about it until someone told me this one... and it sounded like it could work to me. So what the heck, I gave it a whirl... and it seemed to work for me, but who REALLY knows what is fate and what is not.
So here is the idea... if the male constitution is stronger of the two partners you will have a girl and if the female's constitution is stronger you will have a boy. Now here is the tough part, ones constitution is such a subtle thing because it is not determined by 'strength' necessarily, yet more on the health or vitality of your 'being', not to get existential on you... but there it is. You and your partner are usually of similar constitution because you usually eat the same things so if you eat well you have a strong constitution, but ones constitution also takes into consideration being outside and fresh air, exercise, the health of your organs and things like this...
So here is how I kind of personalized it for us (I don't even remember if I told my husband about it... ) I am from a family of three women, my father died when I was very young so men were a pretty foreign being for me. My sister had three girls, so I thought "hey, so will I ...right?!". When we were told with our first baby that we were going to have a boy I just thought "wow... what the heck am I going to do with that!?" it was a real surprise for me (life has a way of throwing those at you right?), and now I know... sort of... what to do with 'that'.. although the energy of a boy is just beyond me! So when it came time to think about another baby I had heard of this constitution story. I was told about how the constitution worked like I said above (male stronger = girl, female stronger = boy) and this friend had done this herself, she said just drink lots of coffee and eat sweets and that is a pretty direct line to lower your constitution.
I did... and we did... have a girl! I also got very sick, so I don't really recommend it honestly but hey... you never know!?
(the above sketch is something I found, it's by Lotte Klaver - click here to see her blog)