<human>: Can you summarize the given text in a few sentences?

Two links: [Mice mothers teach their babies to be afraid] and [Mice fathers can also pass along fears] (scroll down to the section titled "Fear"). 

For people electing to purchase a dog, please take a thorough look at the parents of the litter. You should be able to meet the mother in person, but the sire might belong to another individual. There is *nothing* preventing you from asking the breeder to produce the name/contact info for the sire's owner. A reputable breeder will gladly put you in contact with the sire's owner. Ask both owners about fearful or anxious behaviors -- is there a fear of fireworks? thunderstorms? separation anxiety? strange people? other animals? the vacuum? the mailman? 

Socialization can contribute to a dog's uncertainty with situations, no doubt about that. But now consider what the research is starting to demonstrate: a breeder who fails to socialize a dog adequately is now running a risk of producing those anxious, fearful traits in the puppies *before* there is any chance to socialize them! The pups are starting out behind the 8 ball.
<bot>: if you are going to purchase a dog, check out the temperaments of the parents. Avoid fearful, anxious parents.