Women use gender neutral or male coded pseudonyms or nicknames fairly frequently in geekdom.
This is something of a double-bind. Women who do not use explicitly female names (or whose names aren't coded as such to English speakers) are often assumed to be male unless the woman explicitly identifies herself as female, at least during trivial interactions and sometimes for an extended period. This contributes to the invisibility of women. Women who do use female coded names frequently encounter online harrassment.
See also Pseudonymity in general.
Reasons for using non-female coded names
In many cases women do so because they enter a space (such as IRC, or LiveJournal) where an alias is usually used, and they choose a word they like or a name of someone they admire or similar, and they only then discover that in some venues they are presumed male until they state otherwise. Some may then choose to be especially forthright about their gender, some to announce it when a mistake was made, some to hide it.
Other women are aware of this effect, and choose a non-female coded nickname precisely in order to be identified by others, or at least to people they interact with casually, as presumed-male.
Women who have used non-female coded names
Note: This list consists only of people who are (a) known to identify/have identified as women (b) known to have deliberately chosen male or neutral nicknames in order to be presumed to be a man in some interactions. (In some cases, especially historical ones, this choice may have been their only way to be present in some circles or fields at all.)
In geekdom
- Valerie Aurora, who used her more neutral "Val" nickname for her early career