Brother Nature by Robert Llewellyn
Nina Nash is thirty-three when she decides the time has finally come to sort out her annoying little brother. Little brother Jason is thirty now and a failed dot.commer; Nina, who works for a high tech research company, is going to work out at last what makes Jason tick. She's going to stick a microchip under his skin and, literally, read his emotions on her computer screen. The experiment is more successful than Nina ever could have hoped. And the results of the experiment more astonishing...