Here's an idea for a choice event: a pretty flower in the magic garden bears a strangely colored berry.

Leave the berry alone: increases the chances of this event happening in the future (cumulative with each occurence)After all - berries lead to seeds, right?

Eat the berry: the villager gets very ill, requiring a doctor to heal them. Possibly more than once. Once the villager is healed however, he/she has spontaneously changed genders!

For a twist, an identical event could have different outcomes, for example:

Leave it alone: the berry falls off, sprouting roots and growing into a clone of the villager (perhaps in the opposite gender)

Eat it: Villager gets very ill.