Space-Time Symmetries: P and CP Violation

We begin with a few remarks on an explicit construction of a Bargmann-Wightman-Wigner-type quantum field theory [Phys. Lett. B {\bf 316}, 102 (1993)] in which bosons and associated antibosons have opposite relative intrinsic parities. We then construct $(1,0)\oplus(0,1)$ Majorana ($CP$ self conjugate) and Majorana-like ($C\Gamma^5$ self conjugate, $\Gamma^5=$ chirality operator) fields. We point out that this new structure in the space time symmetries may be relevant to $P$ and $CP$ violation.