Further to FE Hoppy's post, the older CAA Standard required a 7kt crosswind for Vmcg.
The practical real world consideration of strong crosswinds is somewhat ill-considered in the Industry. Taking off with an upwind failure can push the Vmcg up significantly. Typical figures vary from 0.5kt/kt upwards, depending on Type.
Periodic discussion points in PPRuNe relate to the consideration of
(a) crosswind on Vmcg and
(b) the effect of bank angle on Vmca.
A useful report to peruse for which these were material considerations relates to the training accident to the B707-400 at
Prestwick in 1977.
Sobering reading and, in my view, essential for all multi-engine pilots.