Each Twine 2.x compatible Story Format has it’s macro language, and answers to questions like yours depend on which Story Format you are using. The Twine 2.x application’s default Story Format is Harlowe, so I will assume you are using that one.
You didn’t state what you want to happen after the Reader selects one of the two choices, and the possible solutions to your question may be different depending on that. I will describe three of the many possible solutions…
The following solution assumes you just want to send the Reader to a specific Passage based on the choice selected. It uses two Markup based Links to show the two options.
You are a [[young man->Young Man]] / [[young woman->Young Woman]]
The next solution assumes you want to track the choice made using a variable, this solution also forwards the Reader to a specific Passage depending on the choice made. It uses the (link-reveal-goto:) macro to show each link and to forward the Reader to the related Passage, and a (set:) macro to update the variable being used to track the selection.
You are a (link-reveal-goto: "young man", "Young Man")[(set: $answer to "young man")] \ (link-reveal-goto: "young woman", "Young Woman")[(set: $answer to "young woman")]
You can also do something similar to the above without transitioning the Reader to another Passage, using the (link:) macro instead.
You are a (link: "young man")[(set: $answer to "young man")] / (link: "young woman")[(set: $answer to "young woman")]