If you have never had kids you will never understand the love and joy that they can bring.
Thats what I always hear parents say, Ive also heard things like you will never have lived if you dont have kids.
Personally I have enough love and joy in my life and it would be disturbed if I had children. I see parents toil and looked harrassed, financially crippled, disrespected etc.
Our time is our own, as is our money. We can go on holiday when ever we choose, live where we want, drive what ever car I want and my house doesnt constantly look like a tip.