In my Coast Guard days, a young Ensign told me a story of a cruise that involved rescuing some Hatians. She said the Hatians were berthed on deck because there were so many of them. The pregnant ones were having sex, reason being the act could induce labor and their child would be born on U.S. property, thereby becoming a U.S. citizen.
I never checked this story out, but this is what she told me. I could hardly imagine less romantic conditions.
I've heard that story also and I don't doubt it has happened.