Life is precious. Don't take it for granted. You can learn far more about yourself from playing in a losing game than by winning. You are never too old to learn how to cry. It took me almost 54 years.
Sadness is never fun but it can be good.
If this concept causes you to be confused . . . Casual breeding of pets should be avoided. Rent them a video, take them to a farm, buy them a book, just don't take a chance of creating an experience like ours. Instead, teach your children responsibility. Spay and neuter.