Holly Adams is the wife of Bill Adams.
Holly came to Seattle Grace Hospital with her husband, Bill. After a test, Burke discovered that Bill had an ovary. He went into surgery to remove it, but another doctor noted that the Holly's baby couldn't possibly be his because he had blind vas deferens. Burke confronted Holly and she said if Burke was a good friend then he wouldn't tell Bill that she had cheated on him but Burke went in anyway, owing it to him as a doctor.
Holly married Bill Adams. Sometime during the marriage, she got pregnant but when Bill was admitted to Seattle Grace Hospital, the surgeons discovered that the baby wasn't his because he was completely sterile.
Burke confronted Holly about the affair but she told him it was none of his business and although Bill didn't know, they were happy and as a friend, Burke shouldn't tell him. Burke tells him (as his doctor), leaving the fate of their marriage in question.