Level 1
As I see try to use this code in your resource:
/**
* Build a "relatable" query for the given resource.
*
* This query determines which instances of the model may be attached to other resources.
*
* @param \Laravel\Nova\Http\Requests\NovaRequest $request
* @param \Illuminate\Database\Eloquent\Builder $query
* @param \Laravel\Nova\Fields\Field $field
* @return \Illuminate\Database\Eloquent\Builder
*/
public static function relatablesireOffsprings(NovaRequest $request, $query)
{
return $query->where('gender', '=', 1); // e.g. 1 = male //
}