I'm interested what would be the effects on human society if human sex determination system is different, while everything else is the same thus we still have both men and women.

In particular what if humans used Haplodiploid-like system, similar to ants & bees, where female gender (woman) develops from sperm and egg, while woman could produce sons via something like Parthenogenesis, if she decides to get pregnant.

Please note that ALL women & men are capable of reproduction, no hive/colony Queens ruling over infertile workers.

Edit Would there be any effects on the gender ratio? Would the sisters who share 3/4 of genes & brothers who share ~100% of genes be more cooperative with each other and less cooperative with outsiders?


closed as too broad by Hohmannfan, Josh King, Mołot, James, Thucydides Sep 3 '16 at 18:50


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    $\begingroup$ What you want cannot work. One is a unicellular hermaphroditic system and the other only works for simple organisms. $\endgroup$ – TrEs-2b Sep 2 '16 at 21:08
  • $\begingroup$ I am not sure I am reading you correctly. If you say unfertilised egg, do you mean, every ovulation results in offspring? That would change society dramatically! $\endgroup$ – Ludi Sep 2 '16 at 21:22
  • $\begingroup$ No I mean women could produce sons without mating like Parthenogenesis $\endgroup$ – Platypus Sep 2 '16 at 21:24
  • $\begingroup$ Then the question is, what triggers the pregnancy, if not every ovulation? $\endgroup$ – Ludi Sep 2 '16 at 21:26
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    $\begingroup$ If it's like bees, then evolution will produce sterile workers. A female bee has more of her genes in her sister than in her daughter, and so it's in her genes' best interests for her to raise her sisters rather than having daughters of her own, as long as some of those sisters will eventually become fertile queens and able to pass the genes along. $\endgroup$ – Mike Scott Sep 3 '16 at 6:06

For my benefit, I'm laying out the heredity rules for this imaginary society. If I make an error and this isn't perfectly haplodiploid, let's just pretend this is how it works in this nearly haplodiploid society...okay?

So, in this society:

All men have no fathers, but do have grandfathers.

Daughters have mothers and fathers and are equally related to both, just like actual humans.

Fathers have only daughters, no sons, but their daughters all have 100% of their genes.

Mothers have daughters and sons, but 100% of their sons genes come from them, while daughters have only 50% of their genes (just like humans).

All son's of a single mother are 50% related, just like humans.

All son's and daughters of a single mother are 25% related from the sister's point of view and 50% related from the son's point of view. Insofar as a sister can expect a brother to carry 25% of her genes (she has an extra set of chromasomes he does not share) whereas the brother can expect his sister to carry 50% of all of his genes (since he has only one set of chromasomes).

All daughters of a single mother and father are 75% related.

Grandfathers, and greatgrandfathers, and (etc.) are 50% more related to grandsons than granddaughters

Now assuming a Nuclear family with Mother, Father, daughters and sons, we could assume the evolution of this dynamic:

Fathers would care nothing for their sons and would want them out of the household so they would not take resources from daughters. But grandfathers would care and so sons might be expected to leave the house to live with grandparents at an early age.

Fathers would cherish their daughters and would want them to reproduce, particularly in producing grandsons, as they would be as closely related to their grandsons as human fathers are to their sons. As such, they would be interested in spending resources on grandsons equal to the resources they spend on their daughters.

Mothers would cherish sons, and want to lavish resources on them, placing them at odds with their husbands who care not at all for sons.

Mothers would care for daughters but to a lesser extent than sons (50% less).

Sons would be interested in finding a girl and having daughters.

Daughters would be interested in caring for their sisters and encouraging their mother to have more daughters. As such, their interests would be strongly aligned with their father in this regard, who wants daughters as well. However, dad wants the girls to move out and start having sons, the daughters are more interested in caring for each other and helping mom have more daughters.

Daughters have little interest in brothers, but still more than dad has in sons, but not nearly as much as granddad is rooting for grandsons.

So in one form of this society, males take wives. When a son is born he is tormented by dad and mom is punished for the impertinence of having a son. Sisters shelter him somewhat but he must flee the house for grandpa's protection. Daughters are doted on by dad. Daughters care for one another and the house hold has many daughters all encouraging mom and dad to get busy and make more sisters.

Dad is encouraging his virgin daughters to have sons as soon as they can. So, in this world, Sons born out of wedlock to virgin daughters are cherished in the home by mother and grandfather. While son's born to married couples are the focus of malice and strife and, at best, apathy, and are soon driven from the home of their parents into the home of their grandfather.

Dad is watching and periodically marrying off his daughters to suitors. Keeping enough daughters to care for each other and keep mom tamed, but not so many that he does not have enough daughters out there making more grandsons and granddaughters.

Mom continues to want to have sons and will do it on the sly if at all possible. Otherwise, she must periodically deal with punishment from husband and daughters when she produces an unwanted (to them) son.

That's just one imagining. The rules above could be used to come up with all sorts of other possibilities.

  • $\begingroup$ Awesome. I didn't quite understand the math: All son's of a single mother are 50% related, just like humans. wouldn't it be 100%? $\endgroup$ – Ludi Sep 3 '16 at 7:13
  • $\begingroup$ @Ludi each egg is a different recombination of DNA from the mother’s pair of chromosones. Each egg (and the hapliod child it becomes) has for each gene separately a 50% chance of getting it from either copy. $\endgroup$ – JDługosz Sep 3 '16 at 8:35
  • $\begingroup$ Off course! I really learned something! Thanks! $\endgroup$ – Ludi Sep 3 '16 at 9:13
  • $\begingroup$ I left out relatedness of sisters to nieces and nephews. I'll make an edit when I get to a computer. $\endgroup$ – Jim Sep 3 '16 at 10:49
  • $\begingroup$ So your daughters have 150% genes? Half of their mothers (50%) and all of their fathers (100%), specifically? The difference between the amount of genes in a male vs a female makes those percentages the same amount of genes from each side, but that phrasing is kinda funny. $\endgroup$ – Megha Sep 4 '16 at 9:10

The effects would be too many to list

Whatever your model of sexual identity is now, historically most societies identified strongly with binary sexuality. Tolerance for people who deviate from that binary model has varied wildly from society to society, but the measure of binary as the "norm" has not. The overwhelming tendency towards patriarchal systems with varying degrees of repression of women is a strong indicator that sexual identity is fundamental to the human condition.

This thing you propose would change everything. Even physiological changes might well result. If you want specifics, cast your net more tightly, or engender a chat discussion.

  • $\begingroup$ But society stays with binary system, there's still men & woman, it's just the biology what forms into man and what into woman is different. $\endgroup$ – Platypus Sep 2 '16 at 22:44
  • $\begingroup$ The overwhelming tendency towards patriarchal systems is more likely due to the overwhelming tendency of society to be ruled by brute force, of which men have more than women. It is only our gradual abandonment of force as the primary determinant of human relations that has brought about better overall treatment for women. If nature had endowed the women with the better muscles, things would be the other way around. $\endgroup$ – EvilSnack Sep 4 '16 at 17:15

I'll start with fallowing assumptions to make matters simpler. And if I'm writing something wrong excuse my poor biology knowledge and just correct me.

  1. Babies grow in uterus just like regular humans for 9 months & need 18 years to become adults
  2. This "humans" have still two pairs of chromosomes
  3. "Woman" gets two copies from her mother & father, just like us
  4. "Man" gets two copies but just from his mother, so they're basically clone with a different gender, probably using some kind of mechanism similar to Transcaucasian mole vole who doesn't have Y chromosome.
  5. Environment pressure are same to ours (Men are primary breadwinners, fight wars etc)
  6. This 'humans' can't pick sex of their children
  7. Pregnancy is triggered by conception, but through some weird mechanism woman's body decides is it gonna be a girl, or it will completely ignore the sperm chromosomes.

So I draw the relatedness chart below and from what I could see:


  1. Girls (Sister A & Sister B) are connected to everybody with same relatedness like regular human girls, so I expect them to behave and to be treated like human "girls". They would probably serve like mediators since they're genetic bonds holding together this "family".

  2. Due to nearly 100% shared DNA Mother-son connections will be very strong, the saying mama's boy would a have a much stronger meaning in that world

  3. For the father, sons are practically adopted. I'll assume they will be treated as such.
  4. Father will bequeath inheritance to their daughters
  5. Marriages will probably tend toward matrilocal type, since daughters receives the family property it's their job to take care about the parents in their old age
  6. There will be much more single mothers with only sons, if the wife only bears sons why should husband spent any resources on her
  7. Brother's will cooperate much more, I expect lot of brother run businesses
  8. Gender ratio will be skewed more toward boys, since it's in the woman genetic interest to create more "clones". But not too much since single destitute mothers won't have a chance to have many children.
  9. There would be much more abandoned boys then now.
  10. Due to 6-9 there will be probably more conflicts due to surplus of men.
  11. I also expect far more corruption due to brothers & brother's cousins clannishness. If your brother is ~100 DNA related and your mother's sister sons are 50% DNA related (like your brothers now) nepotism will be very strong.
  12. There will be very little if any welfare state.
  13. Society will be collectivist, with nuclear family spanning your clone brothers, fallowed by your mother's sister sons & your sisters.
  14. Patriotism will be much weaker.
  15. I doubt that liberalism & universal human rights will ever happen.

In short the world would be very different place then it's now. More cruelty & corruption, less development & sharing.

