I don't have the same sense the Ox has got... Me, I can tell when a woman is preggers.
Sometimes before she knows.
I told my wife once, "hey, looks like you're going to be an aunt." She thought I was nuts. Three days later, her sister told her that she might be pregnant, and got it confirmed about a week later. She said she had only discovered that she might be that morning. I've sensed it with a few other women as well...
Now, my wife's family has an uncanny ability to determine the sex of the baby before it's born. All of them. They all had a feeling that the same baby in the above story was going to be a girl, and they've guessed several others as well correctly, with only one (IIRC) being the wrong way around.