My boyfriend once slept with his first cousin

On January 29th, Rappler had an advice column about cousin romance:

I recently found out that my boyfriend had hooked up with his first cousin in the past.

He doesn’t think it’s a big deal and thinks that I’m weird for being uncomfortable about it, especially since it happened before we met.

I keep trying to make him understand that it’s not the hooking up part but the incest aspect that makes me uncomfortable, but he doesn’t get it.

There are two responses to this letter. Here is part of the first:

Relationships between cousins spark diametrically opposed views around the world. For example, cousin marriage is illegal in countries such as China, Taiwan, both Koreas, many US states, and of course the Philippines. By contrast, a high percentage of marriages in Pakistan, Saudi Arabia, and some other Middle Eastern and African countries are reportedly between first or second cousins, though statistics are incomplete. Culture, religion, and economics, particularly protection of family wealth, play their part in this disparity of approach.

While the above sheds some light on the frequency and acceptability of cousin marriage, it is silent as to extramarital cousin relationships, though it is likely that these are more frequent than actual marriages. Again, there are laws against such liaisons in some countries, but generally legislation is reserved for cases involving minors, coercion, undue influence, and such. While I am very happy to be corrected, I have found no Philippine law that prohibits sexual relationships between fully consenting adult cousins.

Here is part of the second response:

However, I have experienced that many Filipinos have a gut-level reaction against any kind of incest, so I can understand your discomfort. There are some theories that support this seemingly instinctive aversion to incest. One is the inbreeding avoidance hypothesis (nature); the other the incest taboo (nurture).

Diego’s relationship with his cousin shows that neither the incest taboo (mainly focused on how we do not feel sexual attraction for people we grew up with, such as siblings and close cousins) nor inbreeding avoidance (circumvented by birth control) are applicable to the situation you describe.