Once population control was a no-go topic in nice, liberal circles. For good reason: it leads to distinctly uncomfortable discussions, such as abortion, eugenics, one-child policy and the killing of baby girls.

But with the birth of the seven billionth child some time today, according to the UN - and what this implies for the planet - population control has become acceptable dinner table banter.

The rate of the world's population growth is spectacular. In a New Yorker magazine editorial, Edward O Wilson is quoted referring to the pattern of the 20th century's human population growth as "more bacterial than primate".

What does a ballooning population mean for Earth? Well, there will be increased pressure on finite resources, like water, land and food. It gets worse because many people are also getting richer and consuming more.

Which all means that there will be more carbon dioxide and other greenhouse gas emissions .

I knew some of this when starting my family. But I went ahead and had one planned baby, and then another. Two is a good replacement number and should be enough to satisfy maternal instincts.

I wasn't convinced. The third wasn't really planned. We call her our careless glipsie. But we all know the possible outcome of shared bodily activities, so it's a bit disingenuous to say she was unplanned.

I have contributed to three of the seven billion people on the planet. I am proud of my children. But I am not proud of what their futures may look like. Food shortages. Water wars. Unstable weather.

Last week we saw Julius Malema lead thousands of people to Pretoria on what he called "a long walk to economic freedom".

I presume it was in the spirit of the international Occupy Wall Street Protests against financial greed and corruption that the ANC Youth League leader organised the politically very successful march. The youth marched to deliver memorandums to the Chamber of Mines, the Johannesburg Stock Exchange and the Union Buildings.

The league is complaining about unemployment, poverty and privately owned mines. It is calling for nationalisation and skills programmes for the unemployed.

What is heartbreaking about this march, and about the future of our children, is that in an increasingly overpopulated world, good jobs and adequate food may become progressively more difficult to get.

So, back to the question of population control. Who knows how this difficult topic will be addressed?

But I do realise that although I am privileged to have had my three children, I accept that it is unlikely I'll be having nine grandchildren.