"... Today I saw another family with a rather large number of children. I have a rather large number of children. Maybe big families are making a comeback!!!"As a scientist I say, boy I hope not.
What concerns me the most about the modern trend of having 3 to 5 children per couple can be summed up with simple mathematics. Let's begin, shall we? We'll start off simple with just two parents: Terry and Sherri. Terry and Sherri have a total of four children, two children per parent in the succeeding gene pool. (From now on we'll flex our science muscles and refer to this as the "replacement rate". In our first example, this would be a replacement rate of 4.0.) Now, Terry and Sherri's kids: Mary, Keri, Harry and Barry, pair up accordingly and marry (eww, shallow gene pool) and follow in their parent's footsteps and also have a replacement rate of 4.0. Four kids per set isn't bad, right?
Well, if you're moderately savvy, you'll immediately see a very troublesome trend. Even if we don't consider previous generations - in other words, once each couple gets all children to reproductive age, they die - this mythical population will explode. And it will explode in a hurry - an exponential hurry. If you want to try this at home, get a calculator and put in 2 raised to the 30th power and see how many people you get. That's 1,073,741,824 children in just 30 generations... Yikes.
Now let's consider resources for this exploding population. Food, water, living space (you know, the offspring need enough space to develop, not to mention the couple needs enough space for at least four rounds of hypothetical hanky panky), clothing, and the means to barter for these resources - you know, money. Remember, resources, by definition, are finite. What happens when our mythical population explodes and these basic resources become scarce? Double yikes.
I know this is a horrible comparison, but if you were to watch a colony of bacteria growing in a medium of limited resources - say a petri dish - you'll sit by and witness a colony thrive for a few generations only to eventually collapse and die due to lack of nutrients.
Note that I'm not even considering the possibility of a link between fertility rate and poverty, as this question has been going on for well over 100 years. However, it seems I'm not the only one that believes that higher standards of living can be attributable to lower fertility rates.
I don't mean to be harsh, but at some point our species has to grow up and consider the consequences of our actions... For example: Rather than thinking about yourself and your own selfish needs, how about considering your future beyond a few months? Do you have the means to accommodate that many children? And how about an even bigger question: Do you think our tiny little planet can continue to provide food and water for an exploding population of human beings? Are you willing to risk your child's future, or lack thereof, on your own selfish need to keep having babies?