You are each entitled to the annual exclusion amount on the gift. Together, you can give $22,000 to each donee (2002-2005) or $24,000 (2006-2008), $26,000 (2009-2012) and $28,000 on or after January 1, 2013 (including 2014, 2015, and 2016). Refer to Form 709 (PDF), 709 Instructions and Publication 559.
This can be difficult to stop, and it is highly recommended that such cats are spayed as part of the treatment. Early spaying In the United States, most cats are spayed between 5 and 8 months of age. Many animal shelters and veterinarians are starting to spay female animals at a younger age, even at 2 months. This early neutering does not affect the growth rate, and there are no appreciable differences in skeletal, physical, or behavioral development between those animals neutered early than those neutered at a more traditional age.
The mother cat can be spayed as soon as the kittens are weaned, usually when they around 10 to 12 weeks old. Some shelters will have their kittens neutered at 8 weeks - 12 weeks or 2.0 lbs also. Neutering does not make cats fat or change their personalities regardless of when it's done.