Around the world, there are a number of things that are deemed as being lucky to us. It can often be rather surprising as to what is regarded as being lucky when, to others, it just sounds strange.
Take Japan as a prime example. The Japanese love sumo wrestling as it is part of their culture and wrestlers are held in such high regard that they are absolute celebrities across the country. However, that is not the lucky part that we are talking about right now. Instead, it is seen as being lucky if a sumo wrestler is able to make your baby cry when they are holding it. That is not to say that the sumo wrestler is actively going out of his way to make them cry by doing anything to them, but if they start to do so naturally, then something good is going to happen to you.
It is unsure as to where this apparent belief came from, but it has been around for a substantial period of time and even though that means the initial creation is lost to us, the fact of the matter still remains. If you have a baby and you want to have some luck, then better hope that a sumo wrestler is nearby.