Helvetica and akzidenz are modernist sans-serifs. I would say humanist sans-serifs generally have a more feminine design, so you might want to search my fonts for 'humanist sans'

Typefaces don’t have gender.
(Although there are a few constructed out of bodies/body parts…)

Parisine Plus is one that comes to mind.

Quicksand feels very feminine.

Some people think that a feminine sans serif has one or more of the following characteristics: lighter weight, rounded ends, less mechanical/geometric construction, i.e. more of a handwritten feel etc. Easy to find these. Whether they are actually more feminine is a matter of opinion.
Don

What Jasper said.
Gender associations are not about reproductive organs.

hhp

Notwithstanding the tiresome identity politics spasms that these questions must now inescapably provoke, I would simply suggest you check out Joshua Darden’s Omnes.

http://dardenstudio.com/typefaces/omnes_pro

Also, ironically, Mr Eaves, which I find far more feminine than The Missus.

http://emigre.com/EF.php?fid=213

Omnes in use for Girl Scouts Of America http://dardenstudio.com/notes/fontspotting/girl-scouts-of-america
Don

What's feminine about Girl Scouts?