Any more than two children, and they will develop pack instinct
It goes something like this: One moment you are laughing hysterically at your two-year-old's antics in front of the TV, and the next you are weeping into each other's arms that you'll never again experience the cuteness of a toddler in the house because said toddler is your second child and - as we all know - two children is enough.
Two is one each. Two is a second one to keep the first one amused, so you don't have to. Or, if you happen to be royal, two is an 'heir and a spare'.
But perhaps Kate Middleton didn't get the memo, as she has just announced that she is with child for the third time. In so doing, Kate has confirmed what I have long suspected: when it comes to family sizes, more is increasingly, more.
Family sizes might be shrinking overall, but in these days of status envy, having multiple children is the ultimate indicator that you are better than the rest.
After all, whether you've run an ultramarathon, launched a tech start-up and bought the BMW X5, or merely ensured the continuance of a monarchy, what's left to achieve, except to have another child? Three children leaves no one in any doubt that Kate is "mom enough". So what can she expect?
Firstly, three isn't parenting, it's crowd control. Anything over two children and your offspring adopt the pack instinct. You can do nothing about this.
You are now herding feral cats at the crossroads.
You will find yourself shouting "lock it down!" and hiding in your 'safe place' as opposed to sitting making Playdoh and designing sandwiches to look like caterpillars.
Once you breach the 2.4 children barrier, you may as well continue procreating, opportunity notwithstanding. Three, four, five, what does it matter? Your life, your body, your earning power are gone forever anyway.
Not essential, but you get extra points if you can say you had "three under three", "four under four", etc.
Getting dressed in the morning becomes simpler for everyone. "Is it fashionable, do I like it, is it suitable to today's activity?" becomes "Is it clean and does it fit?"
Three brings a wonderful new dynamic to the family. You will delegate.
It is amazing how well a five-year-old can change nappies.
You will bask in the awe of lesser parents when out pushing one in the Bugaboo while pulling one in the scooter and wearing the other one in a sling.
You get a pass when it comes to screentime. Hell, let them have screens! After all, it's the only time you'll ever get a break.
Strangers will pack your bags in supermarkets out of pity, and people will stop you in the street to tell you, "you have your hands full". Except your elderly neighbour, who will put your gas at a peep by saying, "I had nine", as you struggle past.
You will develop a four o'clock gin habit.