In 2012, Bella was the most popular female dog name for the eighth year in a row. Other top names included Daisy, Molly, Lucy, Sophie and Sadie. Woof.DoggyLoot.com has a list of the top 50 female dog names for 2012.
A number of trends influenced the names owners selected for their pets in 2012. The first book in the "Twilight" series, with its main character, Bella, debuted seven years prior, leading many to choose that name for their female animals. In addition, as pets have become more and more like family members, the use of human names has increased. Thus, names such as Lucy and Sophie have become top picks.
While many names had been popular for years, newer ones such as Rosie, Luna, and Nala (inspired by "The Lion King") were climbing the charts in 2012 as well. Other names also gaining in popularity for girl puppies that year included Layla, Piper, Stella, Willow, Ella and the traditionally male name Charlie.
While breed appears to make a difference in the naming of male dogs, it doesn't have as much influence with female dogs. The popularity of female names tends to remain the same regardless of what type of dogs they are.