spayed or neutered

Reader's　Digest 6月号の記事 "LIFE in these United States" からの引用です。

I ran into a neighbor walking his dog. It was his first pet, so I made sure to lavish praise on the cute pup. Not knowing the gender I asked if it was spayed or neutered.
"Neither." he replied. "She's a shepherd mix."

2/13/2014 に "spaying" のタイトルで "spay"、"neuter、"castrate" を取り入れていますが、ネイティブでもこれらの言葉を知らない人がいるのですかね？　それとも犬を連れていた人はネイティブではない方だったのですかね？