Is that really a health concern though? Single generation shouldn't have risks higher than some already at risk people have no matter who they partner with.

What I've learned is that there's significant risk even for cousins who have children together, so even more for half siblings.

... if the cousins' parents and grandparents are similarly closely related to each other, yes. Otherwise probably not.

My understanding is that 1 generation of first-cousin marriage is very low risk.

The problem comes when you have many generations of family marriages in a row.

The Catholic church tried to make cousin marriages taboo as a way to break up clans and solidify church power.

You're right. It's weird that people are rushing in here to defend inbreeding.

What people might not realize is even when there's not a specific disease caused by the inbreeding, there is still an overall negative effect on health, "inbreeding depression".

Here is a paper that estimates the effect in humans: https://www.ncbi.nlm.nih.gov/pubmed/26131930.

Anything first cousin or closer is bad. Second cousin is kinda bad. Third cousin is OK if it's not happening all the time.

> There's increased risk of inbreeding between these 20 people who (unknowingly to one another) share significant genetic material.

Which is why this whole thing is immoral (not to mention dangerous) to begin with. How can you not assign children to both the (real/biological) father and mother to keep track of these things?

The danger of inbreeding is overblown. It generally takes multiple generations of repeated inbreeding for genetic anomalies to develop.

Half sibling (or uncle/aunt) inbreeding is considerably higher risk than first cousin interbreeding. Only sibling is worse.

I have 2 recessive things that I know I carry, thanks to genetic screening. If I boinked a half sibling, they'd probably be a carrier of 1 of them, and there's a 50-50 chance any resultant offspring would have the conditions.

(Neither would be fatal but both would be severe chronic things-- e.g. hemachromatosis.

There's probably other rarer recessive things that I'm a carrier of and don't even know about.

> I have 2 recessive things that I know I carry, thanks to genetic screening. If I boinked a half sibling

...you could take steps to assure safety first, thanks to genetic screening.

Sure, but A) genetic screening only knows about the common issues, and B) if you marry someone random and don't realize they're a half sibling, you might not bother with genetic screening.

It doesn't change the argument. The fact that the father does not know who his offspring are (and the other way around) is quite bizarre to say the least.

Bizarre is sending messages across hundreds of miles using electrified sand. Men impregnating women and moving on is as old as large scale war, at least.

We're not in a large scale war. Today, this behavior is seen as desirable, without realizing what the effects are.

It's selfish behavior on both the donor and the recipient, and who ends up paying for it are the offspring and most likely society as well.

> We're not in a large scale war.

No, but we're in a large society where men can and do have sex with women (consensually or not) once and leave them pregnant. I'm not making a moral judgement, I'm saying that mostly anonymous sperm donations have been happening long before IVF and sperm banks were a thing, so the results aren't as unpredictable as you paint them.

So let's just enable this behavior even more, on an even larger scale? What you described happens, but it's not comparable to this. A single man's sperm can now be used to impregnate several women with a much lower barrier (as we can see from the article posted here). This issue has also been reported elsewhere, it's clearly becoming more wide spread, and we don't know what we're getting ourselves into, all because of greed and selfishness.

The probability of harm to potential offspring does in fact change the moral argument (which seems to be what you were going for).

Hypothetically, even if it didn't harm the offspring, it must be kept track of who are their real parents.

because genetic testing will also exist in the future

It's not a solution. Not everyone is going to get tested before they get married.

It's interesting how far left/liberal culture today mocks communities that have cousin marriages as "inbred" and "backward", yet they engage in severe and reckless practices that we have no idea how they're going to pan out.

What does "liberal culture" have to do with sperm donation?

Conservative cultures don't allow this practice, they generally still strongly hold to the family as the building unit of society, whereas this practice continues to dismantle it.

We're ending up in a society where people don't know who their offspring are, and where children don't know who their real parents are. This is untrodden ground, and may very well have extremely serious consequences.

i really don't see why. back then there was no IVF and donor sperm would be a way for good old fashioned conservative couples who cant conceive to have the children they always wanted

A conservative couple won't use a sperm donor. The woman will literally be carrying another man's child, not her husband's.

What makes you say so? They wouldn't adopt a kid too? I don't think it's a "left" issue at all for couples. For single mothers, maybe

Adoption is different if done properly. The adopted child should not in anyway be implied or declared to be of the same bloodline as the adopting parents, otherwise we'll end up with the same issue seen here. It's also important that the child know that they're adopted from early on, and not hide that fact.

Whereas artificial insemination is literally having the woman carry another man's child, it goes against conservative values (would they let another man sleep with the woman to impregnate her if there weren't artificial insemination?)

I 'm pretty sure they will / especially if they don't know their biological father.

1. Not everybody knows that they don't know their biological father.

2. My wife is adopted, has had some contact with her biological mother, but zero reliable information on her biological father (her bio mom lies about pretty much everything). She has shown no interest in the various genetic tests out there, even though she has to keep on writing on those health forms at her doctor "unknown" for all the "Does X run in your family" questions.

understand. i would assume though that people who are missing info about one of their parents are more likely to use those services