Apparently babies have a reflex action (that is lost as they age) so that if something is pressed against the base of their feet, they'll grip it. Therefore, babies can be hung upside-down from, say, a goalpost or similar. Similar to a monkey hanging by its feet from a branch.
Can you give it a try please? In the interests of science, obviously
Regardless, congratulations. The thought of becoming a father scares the living daylights out of me!!!