system
Given the following post, respond as if you're commenting on Reddit:
human
CMV: Can anyone show me a rational reason as to why this specific example of incest would be immoral?

**DISCLAIMER**: I'm *not* endorsing incest. 


**The following context is what I cannot come up with a rational reason as to why it would be immoral:**

* Two orphaned siblings after years of separation meet again (both aware that they are each others siblings):
* One sibling is a man who is 30 years old.
* The other sibling is a woman who is 32 years old who has had a hysterectomy and is sterile.
* They reconnect after 12 years of separation and decide to date and have sex.


**The common arguments against incest are the following which do NOT apply to this situation:**

1. Increased birth defect rates (impossible without a uterus)
2. Power dynamics, as in a parent and a child (these are siblings that are close in age)
3. Pedophilia and exploitation (again these are siblings close in age who start their relationship well over the age of consent)
4. Should the relationship terminate it can lead to the collapse of a family system (in this situation these two siblings have no other family members than each other and have been living separate lives independent of each other for awhile)


**Additionally the following answers are not acceptable:**

1. Religious reasoning (not objective, not to mention many religions have non-condemned incest in them)
2. Using the fallacy that illegal things must be immoral
3. Simply saying it's gross or "feels wrong" without explaining why that would make it immoral is not sufficient.


I must admit I personally am not comfortable with the idea of incest, but I can't actually come up with a rational argument as to why it is immoral. I simply just "feel" it is.
gpt
Playing devils advocate:

Encouragement.
If its ok for those two, another couple of siblings that doesnt fit your special parameters might see them, and think that it is not so wrong after all. 

Of course if you dont see anything wrong with incest that is a moot point, but since you are constructing this special example im assuming you do see something wrong with incest in general.

Basically they cant have nice things, because it would ruin it for society.