Unable to Set Text of another Text Object

The Idea: Pressing a button in the canvas will allow the player to select a race. A script is attached to an object which is accessed though the OnClick() function of the button.

The script is supposed to get which race is selected based on which button is pressed and fetch a race description in a Text Object named "DescriptionText".

However a description is not displayed, and I get this error: "NullReferenceException: Object reference not set to an instance of an object GOnClick.GetRaceDesc () (at Assets/Scripts/GUI_Scripts/GOnClick.cs:24)".

I can't see what I am doing wrong, so here is my code:

using UnityEngine;
using System.Collections;
using UnityEngine.UI;

public class GOnClick : MonoBehaviour {

public string race, description;
void Start()
{
    race = "";
    description = "";
}

void Update()
{
    GetRaceDesc();
}


public void GetRaceDesc()
{
    //Button butnText = GameObject.FindObjectOfType<Button>();
    //race = butnText.GetComponentInChildren<Text>().text;
    *(line 24)* race = gameObject.GetComponentInChildren<Text>().text;
    GameObject descRect = GameObject.Find("DescriptionText");


    if(race == "Dark Elf")
    {
        BaseRace raceSelection = new DarkElfRace();
        descRect.GetComponent<Text>().text = raceSelection.CharacterRaceDesc;
    }
    else if (race == "High Elf")
    {
        BaseRace raceSelection = new HighElfRace();
        descRect.GetComponent<Text>().text = raceSelection.CharacterRaceDesc;
    }
    else if (race == "Wood Elf")
    {
        BaseRace raceSelection = new WoodElfRace();
        descRect.GetComponent<Text>().text = raceSelection.CharacterRaceDesc;
    }
    else if (race == "Human")
    {
        BaseRace raceSelection = new HumanRace();
        descRect.GetComponent<Text>().text = raceSelection.CharacterRaceDesc;
    }
    else if (race == "Dwarf")
    {
        BaseRace raceSelection = new DwarfRace();
        descRect.GetComponent<Text>().text = raceSelection.CharacterRaceDesc;
    }
    else if (race == "Orc")
    {
        BaseRace raceSelection = new OrcRace();
        descRect.GetComponent<Text>().text = raceSelection.CharacterRaceDesc;
    }
    else if (race == "Goblin")
    {
        BaseRace raceSelection = new GoblinRace();
        descRect.GetComponent<Text>().text = raceSelection.CharacterRaceDesc;
    }
    else if (race == "Tiefling")
    {
        BaseRace raceSelection = new TieflingRace();
        descRect.GetComponent<Text>().text = raceSelection.CharacterRaceDesc;
    }
    else if (race == "Half Dragon")
    {
        BaseRace raceSelection = new HalfDragonRace();
        descRect.GetComponent<Text>().text = raceSelection.CharacterRaceDesc;
    }
    else if (race == "Werewolf")
    {
        BaseRace raceSelection = new WerewolfRace();
        descRect.GetComponent<Text>().text = raceSelection.CharacterRaceDesc;
    }

    }

}

Thanks in advance for any help.