Curved/angled geometrical forms and association with femininity/ masculinity Is there any research or theoretical reasoning on a strong inclination of human mind to associate curved forms with femininity and angled ones with masculinity?
A similar concept of association is the Maluma/ takete or Bouba/kiki effect.
Another example is font perception. Articles:

15 Fonts Designers Hate And Why | Ambilogo,
Emotional and persuasive perception of fonts by Samuel Juni, Julie S Gross, Perceptual Motor Skills, February 2008,
http://typophile.com/node/58433 (dead link, verified on 26.12.2020),
http://ojad.emu.edu.tr/articles/13/134.pdf (dead link, verified on 26.12.2020).
Yes. Lieven et al. (2015) attributed angular logos to masculinity (and curved logos to femininity). They grounded their hypothesis in the shared perceptual traits:


  "Whereas the prototypical masculine body shape involves an angular
  V-shape induced by a low WCR (Horvath, 1981) and moderate heaviness
  (Furnham and Radley, 1989), a curved (“hourglass”) body shape
  characterized by a WHR of about 0.7 and a slender build is associated
  with femininity and female attractiveness (Singh and Young, 1995)."


They also cite the book Marketing Aesthetics when referring to the general concept. I'm not sure if it contains an empirical study, but it might have more evidence.

I found that previous study when I was researching the literature for my article on font psychology. You might find value in my article as well. I explain more details on the curved vs. angular relationship.

Sources:

Lieven, T., Grohmann, B., Herrmann, A., Landwehr, J. R., &amp; van    Tilburg, M. (2015). The effect of brand design on brand gender    perceptions and brand preference. European Journal of Marketing,    49(1/2), 146-169.

Schmitt, B., &amp; Simonson, A. (1997). Marketing aesthetics: The    strategic management of brands, identity, and image. Free Press.