using magic to determine the sex of a child before being born

[Sharad9]

Matrilineal inheritance of titles and property are the norm in this country. women are expected to be heads of households, and are more common in positions of responsibility Magic in this world allows an individual to determine the sex of their child while it is still developing. There are a number of steps to this ritual. Gestation must be paused during the third month mark. Special herbs must then be ingested regularly at certain intervals. These herbs are specific to the sex that you want, either a boy or girl. Other medicinal herbs are taken to ease or even inhibit the strain of pregnancy (morning sickness, cramps, etc). After an exact amount of time, say one year from the beginning of the ritual, gestation can be restarted as normal. If steps are followed properly, the ritual is always guaranteed to work.

Would this cause a significant gender imbalance of boys and girls?

[brian 333]

Would this cause a significant gender imbalance of boys and girls?

It does in Modern China. It doesn't appear to be a problem in Modern France.

The question is not "Will it have X effect," but, "What are the cultural norms of your society?"

As an example, suppose your version of the god of motherhood absolutely forbids termination of pregnancies but your society defies the divine prohibition. Suppose your matron of motherhood instead allows it only for those who have no daughters. Suppose she insists on daughters as firstborn, commanding firstborn males be sacrificed.

In my homeland the cultural norms are vastly different than that of a bordering nation, and in my travels I have encountered other cultures with still other values. Asking this same question in different parts of our real world would produce vastly different answers.

So, define your society and the answer will come.

[Mechalich]

If the society is matrilineal that creates immense pressure to have at least one daughter to preserve the lineage - just like a patrilineal system creates immense pressure to have sons. As a result, a ritual that can mystically impose gender on a child might well reduce gender imbalance - assuming survivorship is relatively high. If its not - and in most pre-industrial societies it wasn't - then it would great a gender imbalance since most families would have a bunch of girls to make certain at least one survives to adulthood and has children of her own.

However, your ritual, as described, involves prolonging pregnancy by a full year. That's an extreme step that is likely to be undertake only by the elite, so it probably wouldn't have any impact on society as a whole. As a result the big difference is that you will never have a noble household without an heir in this scenario barring some catastrophe that wipes out all the children (which is actually more likely in a matrilineal society because the timeframe for a mother to have children is less than that of a father who can attempt to father heirs on a much younger woman).

[jqavins]

Point 1: Because women hold the power in society, as described in this thread's first post but also in some of your other recent threads which state that only women are ever mages, girl children are clearly more valuable than boys.

Point 2: The method of forcing a child's sex is difficult and expensive.

Result: The rich will have many daughters and few sons^* while the poor will not take advantage of this ability.

Question: What about those special children who are taken to become demigods? Is this any more common among one sex or the other? (You may already have said, but I don't remember.) If so, that would affect the choice of sex, but it could go either way. Some would want to be less likely to lose a child in this way, while others would be eager to contribute to the defense of the world and to gain the consequent honors.

* Due to the genetics of the mage trait, discussed at great length elsewhere, the brothers of a mage girl are carriers of the trait, so even rich families would want a few of those when the mage trait appears.

[akma]

The shortage of males will likely cause men to have multiple wives, especially if there is a "magic gene by father" aspect to it.

If the process would only be a thing of the nobility, and they would want to limit one wife to one husband, they could lessen marriage laws - maybe a noble woman can marry whoever she wants, even a random dirty homeless man. Maybe betrothing a noble wife could be a prize given to men who prove themselves on the field of battle, in matters of state or simply men able to pay a lot of gold. Maybe the noble women could marry whoever they want as long as he has the magic gene. Maybe the rules are strict and finding a husband is extremely hard. Maybe some combination of the above.

If there will be men married to multiple women, it could cause problems other then relationship drama. If a men is married to women of different houses, where will he live? Will he have a room in each house? What happens if the families of two of his wives start a war with each other?
A husband could belong to one household, and marry multiple women from the same noble house (like sisters, or cousins, etc). Maybe it is not quite a husband, but a "breeder", and a noble house could have a bunch of "breeder men" for the women of the household. It could make the society have very restricting norms against incest, because third level cousins could be half siblings, and those norms could trickle down to the common people where they will make much less sense.

[jqavins]

The shortage of males will likely cause men to have multiple wives, especially if there is a "magic gene by father" aspect to it. [And so on]

Or there could be one-to-one marriage with a high tolerance for infidelity.

[TheStranger]

First of all, as jqavins noted, use of this ability is limited to the rich and powerful unless the magic and the relevant herbs are pretty much freely available to everybody. Even then, the method basically doubles the length of pregnancy, and few women would want to be pregnant any longer than necessary (so my wife tells me after five months). So you might have some women using it once to ensure a female heir (either as the first child, or as a last resort after several boys), but other than that I'd imagine they'd just let nature take its course.

But even if you just assume that cultural norms are such that the use of this magic is widespread, a lot depends on other aspects of the culture. If monogamous marriage is the norm, then society will demand roughly equal numbers of men and women so all the daughters have somebody to marry. If there aren't enough men to go around, having a son to marry off advantageously becomes more valuable than another daughter, until it mostly evens out. If men fill other important roles, you'll end up with enough men to fill them, one way or another. If it's more of an "amazon" society with relatively few men kept around for snu-snu, then you could certainly have a gender imbalance. Or you could have more elaborate and formalized expectation - your first child shall be a girl to secure the line, your second a boy to marry well, your third a girl to become a priestess, your fourth a boy to become a soldier, etc. Bonus points if you make up a good rhyming catechism that goes a dozen kids deep.

The idea of men carrying the magic gene complicates things, but it doesn't necessarily change that much. If the father is a known or suspected carrier of the magic gene, then women would probably want to have at least one son. But still, the cultural norms of monogamy vs. polygamy would be the bigger driver of whether you needed as many men as women.