Philipp Marx
Founder of RattleStork
Philipp Marx is a founder of RattleStork and a former international sperm donor. He writes from first-hand experience about sperm donation, co-parenting, and alternative paths to parenthood.
Before founding RattleStork, Philipp donated sperm in several countries. That experience showed him how differently people approach donor conception, trust, personal boundaries, and co-parenting.
At RattleStork, he combines that perspective with publicly available sources and practical guidance for donors, recipients, and prospective co-parents. His personal experience is not a substitute for medical or legal advice.
Articles by this author
Total published articles:220
Erection Problems When Trying to Conceive: How Pressure, Timing, and Health Interact
When trying to conceive turns sex into a timed task, closeness can quickly feel like a performance test.
Nominal condom width: what it means, how to convert it, and how to find the right size without a calculator
The nominal width is a millimeter measurement that describes the width of a condom in its flat, unrolled state. It is not a body width, not a diameter, and not a secret lab number; rather, it is a packaging specification that makes it much easier to compare products than labels like Standard, Regular, Large, or XL.
Swallowing semen: healthy or risky? STI risk, pregnancy, and clear answers
Swallowing semen can feel like an awkward question, but medically it is usually pretty straightforward.
Blowjob: Oral sex without pressure – consent, hygiene, protection
A blowjob is oral sex on a penis, and it is only good when everyone involved feels safe and respected.
Cunnilingus: Oral Sex on Women Explained Clearly and Realistically
Cunnilingus, often just called going down on someone, means oral sex on the vulva.
Foreplay: ideas, communication, desire, and safety without performance pressure
Foreplay is not just a quick lead-in before penetration.
Petting: Intimacy without sex, understanding risks and setting boundaries
Petting can create intimacy without penetration, but it often raises the same questions: what counts, where are the boundaries, when does pregnancy risk become real, and which sexually transmitted infections can still spread?
STIs from Blowjobs: What the Real Risk Is and How to Protect Yourself
You can get a sexually transmitted infection from a blowjob.
Can You Get Sick from Oral Sex? Cunnilingus and STIs, Explained Realistically
A lot of people search for getting sick from oral sex or STIs from cunnilingus and want a simple yes-or-no answer.
Starting the birth control pill: how to choose a formulation and begin safely
The birth control pill is hormonal contraception that can prevent pregnancy very reliably when taken correctly.Morning after pill: what matters now, how it works, and when to test
The morning after pill is emergency contraception after unprotected sex or a birth control accident.
How much semen does it take to get pregnant?
In theory, a single sperm cell is enough to fertilize an egg.
Am I Too Old to Be a Sperm Donor? What Age Limits Really Mean
If you are thinking about sperm donation and you are no longer in your early 20s, the same question usually lands on the table first: am I already too old for this? The honest answer is neither a simple yes nor a simple no. There is no magic number that applies everywhere. What matters is a program's internal age limit, your screening, and whether your profile still makes medical and practical sense for donor selection.
How many eggs does a woman have? Ovarian reserve, ovulation, and age explained simply
Women are born with a finite ovarian reserve that declines over the course of life.
Signs you’re not getting pregnant: when an evaluation makes sense
Clear signs of infertility are rare.
Hymen: what it really is and why it proves nothing
Many people look for information about the hymen, also called the vaginal corona, and wonder whether you can tell virginity from it or whether it always tears and bleeds the first time you have sex.
Pregnant from anal sex? What’s possible and how to assess the risk realistically
Anal sex by itself can’t cause pregnancy, because sperm would have to enter the vagina to fertilize an egg.
Parentage law in the United States: what donor-conception families need to know in 2026
The United States does not have one national parentage rule for donor-conception families.
Pregnancy records in the United States: what is documented, how to read it, and what digital access really means
The United States does not have one national maternity booklet like Germany's Mutterpass.
Co-Parenting Across U.S. State Lines: What Actually Changes and How to Keep It Workable
Living in different states does not automatically make co-parenting fail, but it does raise the stakes. Parentage, decision-making, travel, money, and relocation all need clearer rules when a plan has to work across state lines. Florida, Illinois, Kentucky, Minnesota, Arizona, and Washington are good examples of how differently the rules can look once a plan has to cross a state border. This guide focuses on the pressure points that usually break a weak agreement and the defaults that make a long-distance plan easier to live with.
PEP after a possible HIV exposure: What you need to know in the first 72 hours
PEP is an emergency medical step after a possible HIV exposure.
How to use a condom correctly: a step-by-step guide
A condom works best when you put it on before the first contact, leave room at the tip, roll it all the way down, and remove it carefully afterward. The steps are simple, but the small details decide safety, comfort, and whether it stays in place.