It's always been that clear-cut to me.
There are species of fish that, depending on their sizeand wieght, they can transform back and forth between male and female.
There are species of a flatworm in oceans, that have one or two penis, and which ever flatworm stabs the other one first, the one being stabbed first gets pregnant.
There a few all femaleonly species , that pop-out exact clones of them selves. There is no evidence of all male only species, and certainly no all male species that pop-out exact clones of them selves.
X is more complex the the y for two primary reasons: 1} mathematically there exist more lines-of-relationship, 2} more chance for synergetic relationships that more likey to occur with a larger set of relationships. We know from lab experiements, that when asked a series of questions, womens brains tend to be more active in both hemi-spheres of the brain.
Woman have a uterus/womb, men have a prostate gland. If any here believe the functionality of prostrate gland is more complicated than the functionality of uterus/womb, I love to see the evidence of such.
Woman is the most complex entity of Universe, putting aside scenarios of two women, one woman and one man, or a who Earth or solar system or finite Univrse.
The 2ndayr symbolism for man and woman should be as follows and not the old venus mirror vanity symbol and mars shield and spear.
1( * * ) as complex bilateral consciousness
2} Woman as closed triangular set .... /\ ......... and with internalized two ovaries or eyes, hemi-spheres set etc of bilateral \* */ tho I dont have mechansim to close the top line here,
3} Man as open triangular set *Y* whereas the testes are externalized, ears, eyes two hemi-spheres bilateral set,
4} when man symbol is placed inside of woman symbol, we get a birds-eye-view of the minimal 3D structure of Universe, the tetrahedron \Y/.
LINK
There exists, generally speaking, three X chromosomes for every y chromosome in Universe. Xx-Xy so No wonder men feel so inferior ;--)