No dog sex
Bethesda has revealed more Fallout 4 information at QuakeCon today. There are 12 companions in the game (including Dogmeat, the dog) and Bethesda says they can all be romanced regardless of gender.
“The human ones,” Bethesda’s Head of Marketing, Pete Hines clarified.
So they’re all bi and so is your character (unless you’re locked into one romance and you do a straight one so your character may be straight, I guess, though not necessarily). Point is, as long as it’s human, you can bone.
No fucking the robot.
QuakeCon 2015: Fallout 4 Players Can Romance Companions [IGN]