The first crossing of a poodle with a Labrador does result in variations in terms of appearance, size, coat and temperament. So while most Labradoodles share some common traits, their appearance and behavioral characteristics can be widely variable. The variation mostly applies to early-generation Labrador-poodle crosses, and not to multigeneration Labradoodles or Australian Labradoodles: Once a Labrador-poodle cross has been selectively bred to other Labradoodles for 4 generations or more, then there is much greater consistency for all the selected aspects. Labradoodles' hair can be anywhere from wiry to soft, and may be straight, wavy, or curly. Some Labradoodles do shed, although the coat usually sheds less and has less "dog odor" than that of a Labrador retriever. Regular haircuts, bathing and brushing are necessary to maintaining a healthy coat. Labradoodles often display an affinity for water and strong swimming ability from their parent breeds. Like most Labrador retrievers and poodles, Labradoodles are generally friendly, energetic, and good with families and children. Their parent breeds are both among the world's most intelligent dog breeds, in which the poodle is believed to be among the smartest (second, after the border collie). There is no consensus as to whether breeders should aim to have Labradoodles recognized as a breed. Some breeders prefer to restrict breeding to produce F1 hybrids (bred from a poodle and Labrador rather than, e.g. F2 hybrids bred from two Labradoodles) to ensure relatively uniform genetics among the Labradoodles, while maximizing genetic diversity of individual dogs to avoid inherited health problems that have plagued some inbred dog breeds. A large number of Labradoodle and Australian Labradoodle breeders who are ethical and well regarded, were previously breeders of purebred dogs. For many of these breeders, the inherent concerns with health and temperament for dogs who are being produced through repeated and more closely inbreeding and line-breeding led them to the Labradoodle or Australian Labradoodle. The WALA and ALAA maintain open stud books whereas the ALCA maintains a closed stud book. Others are breeding Labradoodle to Labradoodle over successive generations, and trying to establish a new dog breed. These dogs are usually referred to as "multigenerational" (multigen) Labradoodles or multigeneration Australian Labradoodles. Australian Labradoodles also differ from Labradoodles in general, in that they may also have other breeds in their ancestry.