Good puppies start long before breeding ever takes place. Both parents need long-term care -- what dog people call conditioning -- to produce the best offspring. This means regular veterinary care, screening for genetic problems, pre-breeding tests, and regular exercise and good nutrition.
A universally unique identifier (UUID) is an identifier standard used in software construction. A UUID is simply a 128-bit value. The meaning of each bit is defined by any of several variants. For human-readable display, many systems use a canonical format using hexadecimal text with inserted hyphen characters.
An avatar's attachments keeps it's instance UUIDs when the user teleports or moves from one region to another (they are not kept when an avatar logs off). The instance UUID is what is returned by llGetKey and other functions. Account UUIDs are assigned during the creation process and never change.