We want to provide women worldwide with an effective and affordable means of natural family planning that they can trust and rely on throughout their fertile life period.


Dr. Stephan Gerhard

Stephan has a Master in Neuroinformatics and a PhD in Neuroscience from ETH Zurich. He is in charge of the operative leadership of Lady Cycle and for the mobile apps development.

Dr. Patricia Milz

Patricia has a master and PhD in Psychology from the University of Zurich. She works as a junior principal investigator at the KEY Institute for Brain-Mind Research in Zurich. She is responsible for the conceptual design of the Lady Cycle apps, acquisition of funding, and the establishment and coordination of scientific collaborations.

Our Story

The story of Lady Cycle begins in 2009. We were in the midst of our studies at University and ourselves looking for an effective natural family planning (NFP) method.

In the context of a biopsychology lecture, Patricia delved into the topic of the female menstrual cycle. She became aware of how crucial hormonal balance was to the body and also how hormonal contraceptives could impact it. The more she learnt, the more she became convinced that she herself did not want to take hormones. Instead she wanted to live with her natural cycles.

Based on his biology background, Stephan could easily relate. However, what alternatives to the pill were indeed effective? Getting pregnant amid our studies was definitely not an option and methods of natural family planning (NFP) were considered very unreliable, or not?

Well, we wanted to know and began extensively investigating the topic. At first, we were confronted with a vast number of very ineffective methods with unacceptably high rates of unwanted pregnancies. This was quite discouraging. However, eventually we came across something quite interesting, a book entitled «Natural Family Planning today». This book – besides comparing very many methods –introduced one particular method, which – to our surprise – perfectly fulfilled all our criteria: the symptothermal method of the NFP workgroup.

The symptothermal method was not only natural but very, very effective! If correctly applied, it was as effective as the pill. And most importantly, this was not an unsubstantiated claim driven by financial interests, but a scientific finding validated across several independent studies – without conflicts of interest!

We had to give this method a try – and we did with no regrets! Patricia learnt more and more about her cycles. She learnt how she could identify her fertile days. For the first time in her life, she knew when her ovulation was approaching, when it had occurred, and the exact day of her next period. Cycle by cycle, we trusted the method more and more.

But there was a problem. The symptothermal method required to track temperature and cervical mucus observations with pen and paper. Also, to identify the fertile days, all the rules of the method needed to be applied manually. After a while, this got quite tedious. At the beginning of the smartphone age, there needed to be a better way.

Stephan came up with an idea. How about we combine our computer science and biology background and implement the rules of the symptothermal method into a smartphone app. That was it, thought Patricia, and we both started dedicating evening after evening, weekend after weekend, to develop the Lady Cycle app.

Originally, we had not planned to release the app publicly. However, it worked so reliably and saved so much work and time, we felt that other women would most likely profit from our app as well. So, in 2011, we published the first version of Lady Cycle in the Android App Store.

The demand exceeded all our expectations. Without any marketing, our free app was downloaded more than 100’000 times – worldwide! We received countless e-mails from women and couples that thanked us for having helped them to effectively conceive or get pregnant – when they wanted to. The media, renowned consumer protection agencies, and gynecologists started to show interest in our app.

The positive feedback we received was overwhelming. However, the great demand went well beyond what we could supply on an unsalaried basis in the long-run. In order to cover the substantial costs involved with developing the app further and supporting our users sustainably, we decided to professionalize the Lady Cycle project in 2018. For this reason, we offer, since 2019, a premium version with exclusive, additional features – besides our donation option.

We would like to express our gratefulness to everyone who supports and has supported us – be it financially or with volunteer work. We feel honored to be able to contribute – with Lady Cycle – to the health and well-being of so many women and couples worldwide.

Patricia & Stephan