"A baby will fix it"

The baby is the next thing people are least willing to say they're expecting to fix anything, and it's also the one with the most research, so I'll be careful and I'll be specific.

The research is mixed, and the people who've done most of it say so. Katherine Nelson, Kostadin Kushlev and Sonja Lyubomirsky reviewed it in 2014 and concluded that whether parents are happier than non-parents is the wrong question. What they found was that parents are less happy to the extent that parenthood brings more negative emotion, money trouble, lost sleep and a strained marriage, and happier to the extent that it brings meaning, the satisfaction of basic needs, positive emotion and a fuller social role. Both sets of things arrive together. The earlier study by Nelson, Kushlev, Tammy English, Elizabeth Dunn and Lyubomirsky found that across three approaches, parents and especially fathers reported more happiness, more positive emotion and more meaning in life than non-parents.

Against that, the panel studies. Clark, Diener, Georgellis and Lucas, in twenty waves of the German data, found complete adaptation in life satisfaction to the birth of a first child. The rise came and went. Ivana Anusic, Stevie Yap and Richard Lucas, in an Australian national panel, found a slight decrease in positive feeling after childbirth and a slight increase in negative feeling, relative to what would have happened anyway. Slight, and in a national sample, and not the scene on the front of the pram catalogue.

What I take from all that is this, and the interpretation is mine. A child changes the outline of a life more than anything else on the list, and it also changes the Thursday more than anything else on the list, and the two changes point in different directions. The outline gains meaning, the thing Nelson's studies keep finding. The Thursday gains sleep loss, money trouble and the end of most of the time you had. If the hum was a level, it will be there in the nursery at three in the morning, with less sleep to fight it. If what you were missing was meaning, a real absence of anything that mattered, then a child might be the rare next thing that's actually a fix, because meaning is a cause and it's one a child does supply.

Which is why this one, above all the others, needs the Thursday question rather than the preview. The preview is a Sunday morning. The Thursday is the one with the nursery drop-off and the work you haven't done and the row about whose turn it is, and a child doesn't stop the hum on that day. What a child does is make the hum matter less, for some people, because there's something in the afternoon that outranks it. Whether you're one of those people is not something the preview can tell you.