  The transversity distribution for $u$ and $d$ quarks is usually extracted
from data on spin asymmetries in Semi Inclusive Deep Inelastic Scattering
(SIDIS): however, due to its chiral odd nature, it has to be coupled to another
chiral odd function, typically the Collins or the di-hadron fragmentation
function. A recent suggestion of considering SIDIS data involving ratios of
spin asymmetries and avoiding a knowledge of the Collins function, is briefly
discussed. New measurements, involving ratios of cross sections, are suggested.
They would allow a direct extraction of the transversity ratio,
$h_1^{d_V}/h_1^{u_V}$. Numerical estimates are given.
