[waveman2]

From personal experience I suggest you never buy a children's book on your own account.

There doesn't seem to be a way to tell Amazon "Hey this purchase was a one-off, don't use it for recommendations".

[gaius]

Sure there is, in the top left there is a link for "<your name>'s Amazon", click that, then in the toolbar in the middle click "Improve your recommendations". You'll get a list of all your purchases with a checkbox by each one to disregard it.

[s_kilk]

Or when you buy some newborn-baby clothes or equipment as a gift for a relative and all you see on Amazon thereafter is childcare products.