Can someone legally sleep with their adoptive sister's biological brother?

Like, they obviously wouldn't be related, but if the biological brother was not adopted along with his sister and they meet later in life, could he legally marry his blood sister's adoptive sister?

Also, I'm not planning on sleeping with anyone. This is for a fanfiction. Don't ask.

Marvin2016-10-02T22:04:24Z

The can legally sleep with thier biological brother or sister.

Quit listening to urban legend.

I take the thumb down as your admission of complete ignorance.

?2016-10-03T06:17:31Z

Yes.

熊冰冰2016-10-02T19:38:38Z

Yes, of course he could. They are no relation.