Implicating brother → male
Link to implication

Reason:

By definition brothers are male. Any other genders wouldn't really fit anyways.

Edit: brothers -> male as well.

I have doubts about this one for the same reason the sister thread is getting similar doubts brought up: If I saw a picture that seemed like brother/s but one of them was a maleherm or cuntboy and a male, I think I'd still feel like they were brothers if the presentation seemed male everywhere else except for their genitals.

While I'm sure these implications would work for the majority of images, it's about whether or not there's a small number of exceptions than that could easily break the ability for this implication to work well.

In real life, intersex people are still considered to be someone's brother or sister, usually based on whichever binary gender they seem most similar to. So the use of these terms "brother" and "sister" isn't as exclusively male-only/female-only as this implication would make it into. Which all makes me wonder if this implication is a bad idea. Would it be artificially redefining these words to be more narrow than how they are used in real life if we exclude the ability to call intersexed siblings a "brother" or a "sister" of someone else? If someone didn't want to see intersexed results in their search, they could and should "-intersex" from the search just like they'd have to do with any other search on the site. It's not very many images that this situation is ever going to come up for. But I think it needs decided one way or the other before this set of implications can be accepted/deleted.

Well we could always go with xister and xother. Yes, I actually found a few wikis with "hir".

But seriously, I'm leaning towards -1 on these now for the reasons already described in this thread and the other

The terms are handled pretty loosely as it is. The very slight convenience of having it imply male isn't worth the risk of adding an incorrect gender tag to a post. So for now this implication is denied.