From a psychological perspective, would you say that incest relationships are unhealthy?

I will not limit my perception regarding this issue to only human. Incestous relationship will naturally present itself when there’s scarcity of distant genes for reproduction, this can even be extended to as far as mutual partnership between member of the same direct bloodline.

I can say that it has healthy psychological foundation but find it more closely related to a temporary beneficial step of relationship where exploration hasn’t been done by related individuals (or when certain obsession occur), at least until a better/different opportunity slip inside.

Lots of good reasons not to, number one; eeeeewwwwwww

Unhealthy from a power perspective (parent having power over the child, for example). Unhealthy from the fact that it’s taboo and must remain a secret, also.

The argument against consanguineous incest (blood relations) doesn’t have to be logical. The foundation is biological:
20–36% of children from parent-child or sibling-sibling will die or have major disability due to the inbreeding. Of 29 offspring resulting from brother-sister or father-daughter incest, 20 had congenital abnormalities.

I’d suggest that the human prohibitions against affinity relationships hark back to the days before paternity and DNA tests, where society erred on the side of caution.

As to affinity (non-blood) relationships,
It’s adorable if a couple meet and bond in kindergarten and later marry.
It’s creepy if they meet later, but their (single) parents have met first, and marry?

If you dismiss the biological issues (covered in detail by @ibstubro), then, in my opinion, it’s no more objectionable than any other relationship. And in some cases, it might be exactly what the parties needed.

There’s sibling incest, there’s parent/child incest, and there is close relative incest. (and probably some other variants as well).

Again, dismissing the biological dangers, the real question is: is there a deep emotional bond (love) between the parties? That’s the key.

More inhibiting than the genetic risks of inbreeding, cultural condemnation produces feelings of guilt when incestuous thoughts arise that make seeking sexual partners outside of the family more desirable. Incest involving children and early adolescence often produce sever psychological harm, though incest among adults may not.

A son who wishes to hump his female parent may be left disappointed however willing she may be, she probably had the mother of all headaches.

I find it very, very hard to believe that the majority of instances of parent-child incest did not also involve gross sexual imposition of a minor, ergo, psychological trauma (manifesting as.. stockholym syndrome?). I’d wager that many instances of incest are a result of manipulation post sexual trauma. Serious power play. I suspect that there are very few instances of incest that don’t stem from some level of abuse, mentally or physically.

I’ve heard “incest is best” but I’ve never tried it to find out.