Apparently yes since:
If you believe those quotes are out of context, please read them whole, as usual...
I said that because of the recent situation in America. That wasn't specifically pointed towards this subject.
If you consider this then one has to understand which question is being asked:
'Is incest bad?' (e.g. inbreeding) or
'Is incest wrong?' (ethics)
Even if we believe that consenting adults should be able to have sex with whomever they please, reproducing with a close relative has serious drawbacks. I should just leave this here:
One study found that 40 percent of children whose parents were first-degree relatives were born with autosomal recessive disorders, congenital physical malformations, or severe intellectual deficits. According to the study, when first-degree relatives mate, the risk of their child suffering from an early death, serious birth defect, or mental disability increases to almost 50 percent.