Do you think raising a puppy is hard?  Try raising a puppy that is pregnant with a litter of puppies herself!  What most pet owners are surprised to learn is that dogs can become sexually active and mature early in their lives.  Listed here is everything you wanted to know (or not) about your dog’s sexual health but were afraid to ask.  When Does a Dog Become Sexually Active? Dogs can become sexually active at a surprisingly young age, which is dependent upon their gender. Female Dogs Female dogs experience their first estrus at 4 – 6 months of age.  In general, small breed dogs reach puberty earlier, while larger dogs may not “come into season” until 2 years of age.  As dogs grow older their heat cycles may become irregular, but they will never stop ovulating entirely.  If heat cycles disappear, an underlying health issue is likely to blame. ...