  We have studied a sample of more than 25 000 young stars with proper motions
and trigonometric parallaxes from the Gaia DR2 catalogue. The relative errors
of their parallaxes do not exceed 10\%. The selection of stars belonging to
active star-forming regions was made by Marton et al. based on data from the
Gaia DR2 catalogue by invoking infrared measurements from the WISE and Planck
catalogues. Low-mass T Tauri stars constitute the majority of sample stars. The
following parameters of the angular velocity of Galactic rotation have been
found from them: $\Omega_0 =28.40\pm0.11$ km s$^{-1}$ kpc$^{-1}$,
$\Omega^{'}_0=-3.933\pm0.033$ km s$^{-1}$ kpc$^{-2}$ and
$\Omega^{''}_0=0.804\pm0.040$ km s$^{-1}$ kpc$^{-3}$. The Oort constants are
$A=15.73\pm0.32$ km s$^{-1}$ kpc$^{-1}$ and $B=-12.67\pm0.34$ km s$^{-1}$
kpc$^{-1}$, while the circular rotation velocity of the solar neighborhood
around the Galactic center is $V_0=227\pm4$ km s$^{-1}$ for the adopted
Galactocentric distance of the Sun $R_0=8.0\pm0.15$ kpc.
