The gay spock problem is when you have two characters interacting who have the same pronouns, and it gets confusing. For example,

He brushed his hair aside and spoke gently into his ear, “you are my one true love, my light and laughter, my reason to live.”

Who’s the one speaking? Kirk or Spock?

Likewise, if Alice and Barbara or Adam and Bob are your two example people, you’ll run into the gay spock problem.