newtonsoft json serialize enum as string

I want to serialize enums in the serialization object as string instead of numeric value.

Not like this:

},
"gender": 3,
"birthDate": "1980-01-01",

Like this:

},
"gender": "Male",
"birthDate": "1980-01-01",

I'm using following:

using Newtonsoft.Json.Serialization; // package

JsonConvert.SerializeObject(userObject);