For some shy dogs, men can be scary. Maybe because men tend to be bigger and taller and have deeper voices.
We can help our pups get used to the man of the house by taking things slowly.
In the beginning, man will completely ignore pup - no eye contact, no approaching, no touching, no talking.
Man should enter rooms sideways, lady of the house should let puppy know that man is arriving so pup isn't surprised.
At first only the lady will hand or toss treats to the dog. See the below article for research on why the dog should not be forced to approach the man for treats:
Use desensitization and counter conditioning. i.e. man stands 100 feet away, lady gives treat, man leaves. Next time, Man tries 95 feet, and so on. Always stop the exercise while pup is having a good time.
An even better way is found in Grisha Stewart's "Behavior Adjustment Training" where the man stays still from a great distance away, lady walks pup towards man, stops at a comfortable distance (maybe 100 feet, maybe 500 feet), then runs away in the other direction. Each time, lady and dog can try getting a little closer but not so close that the dog becomes scared. That was just a simple example. Much more detail is in the book.
After that goes well, Man continues to ignore pup. If pup decides to approach man, man can toss a treat behind pup. This is a two fold treat. The gets a tasty treat, plus relief from pressure. Man can also toss a treat then walk away - once again relieving pressure.
It can be months or even a year before man should be allowed to touch the pup. And then only if pup requests being touched or petted.
Before petting, start with handling exercises:
Also man must be aware of how he approaches, touches, socializes with pup
Always let pup approach but if he has to approach, don't do it directly, walk in an arc - his side to the pup's side.
Don't lean over the pup, don't hug the pup, don't pet on top of the head. More on socializing:
Correct way to meet a shy dog: http://www.youtube.com/watch?v=OpwOTXLpXaE&feature=plcp
Don't offer a hand: http://www.youtube.com/watch?v=cOm5nuMVOvg&feature=plcp
Don't get in dog's face: http://www.youtube.com/watch?v=SjtCJqxlKJk&feature=plcp