Genes on the 23rd chromosome pair (XY or XX) cause one group of cells to develop and the other to atrophy ... creating the nucleus of what will eventually be ovaries or testes.
(Genes on the 23rd chromosome pair; cause; one group of cells; to develop) (one group of cells; to develop; )
Genes on the 23rd chromosome pair one group of cells
cause to develop
one group of cells to develop