A San Francisco couple just had a baby on Thursday, kind of by surprise. After tweeting about the entire ordeal, new dad Marco Rogers tells KCBS Radio that he and his wife Aniyia Williams had no intention of having a home birth, but after using an app to track Williams' contractions, that's just what ended up happening.

"I’m a software engineer, I work in tech," says Rogers. "I’m that guy, like the furthest from a healthcare professional as you can get."

Williams woke up with contractions in the morning, and the pair were using an app called Full Term, with Williams using the word "banana" to indicate when a contraction started and ended. Only, as Rogers explains, they got off track somehow, or the app wasn't prepared for how fast Williams' contractions would escalate.

Also, they called Kaiser hospital a couple of times and were told to stay at home even though contractions got to be just five minutes apart — Kaiser told them to stay home until they were two or three minutes apart, and they had already been at this about 10 hours at this point.

But then it all came hard and fast, and as they were headed to the garage to get on the way to the hospital, Williams said they couldn't make it, and she could feel the head already. She told her husband to grab the What to Expect When You're Expecting book, which has an emergency section on delivering a baby, and they made it back up to the bedroom where he and his father in law delivered baby Noemi a few minutes later, before EMTs could arrive.

And, naturally, they used the book as a cutting board for the umbilical cord — and even though Williams told her husband to torch the thing afterward, he didn't, and saved it in a Ziploc.

Rogers described the whole thing in detail in a series of tweets that have gotten plenty of traction in the ensuing days — and we'll forgive him for sneaking in a plug for his wife's startup and reprint them here.