John Mueller from Google said on Twitter that links from adult or pornographic sites are not automatically considered spam by Google. In fact, he said they are not always even problematic for your site's rankings.
John Mueller wrote, "Adult sites aren't automatically spam, and links from them not automatically unnatural / problematic."
@Marie_Haynes Adult sites aren't automatically spam, and links from them not automatically unnatural / problematic.
— John Mueller (@JohnMu) August 5, 2016
Truth is, we covered this before when we wrote Google: Adult Web Sites Are Not Automatically Spammy Web Sites.
It is perfectly find to have links from adult sites, assuming those links are natural links and not against Google's link guidelines.
I do see it way too often that people will simply disavow links that are from adult sites, because they are from adult sites. That is not always necessary or a good practice.
Forum discussion at Twitter.
