Reading my ACCEPTED y combinator application | how to get into YC

Kathryn Cross, founder of Anja Health, reads through her accepted Y Combinator written application question by question, explaining how she wrote it and, looking back, what was true and what was exaggeration.

00:00Intro — the written application is the thing

• YC is the best startup accelerator, and the written application is the first gate and the biggest barrier (the stage before the $500K investment). Only 7% of written applicants advance to the next round (the interview, which is the final one).
• She had five YC founders read and refine her application, applied twice, and got in as a non-technical solo female founder — beating the odds, by her own assessment.
• Anja Health (founded 2021): a company that helps expecting parents preserve stem cells from the umbilical cord and placenta for treating future disease in their family.

00:59Who writes the code / technical experience

• Her answer: "I'm a technical front-end product designer who designed the entire product using no-code tools and front-end skills." Three CS courses, able to code mostly on the front end → enough to stand up an early MVP by vibe coding, but not fully technical. What mattered was selling her ability while staying honest.

01:30Disclosing that she's a solo founder

• At the time she didn't know being a solo founder is a negative. It's disfavored because there's no one to lean on when things get hard — and after four years, she says it's genuinely true. For her next company she wants a thought partner to lean on.

01:56Describing the company & 02:15 how to land the one-liner

• The under-50-character description: "Preserving stem cells at birth for preventative care." But over time the most effective one-liner evolved into "freeze stem cells from the umbilical cord and placenta to treat future disease" — something she learned by making more than 2,000 TikToks.
• The URL is angelahealth.com (originally use.com, but the verb 'use' was wrong, so adding 'health' made the context clear).

02:42What the company will build

• "A full-stack experience for cryopreserving cord blood collected after birth for disease treatment and anti-aging purposes." Very technical phrasing that she wouldn't use now. She also mentioned expansion possibilities like genetic testing and immune cell banking, but over four years media expansion and scale proved more useful, so she didn't go there (she looked at white-label genetic testing and immune cell banking and dropped both).

03:32Where she lives & 03:35 LA vs NYC vs SF

• LA at the time of applying (where she grew up), New York now. It surprised her that YC backed an LA founder — she assumed the order was SF > NYC > LA.

04:06How far along (traction)

• On the first application: zero customers, no traction at all. On the second, following the advice that even a little traction beats the majority of applicants (who have none):
  • A complete end-to-end collection experience, beta customers due to give birth within two months, and a waitlist of 6,000+ built at $0 CAC (a 30,000+ email and social community, built on her own TikTok following).
  • A team of five (herself as CEO, a marketing lead, two sales consultants — all contractors, later replaced because she managed them poorly).
  • At least one partnership each with a doula group, a surrogacy agency, and an OB-GYN practice. Doulas were the most useful (reachable by Instagram DM and text), while surrogacy agencies and OB-GYNs were institutional and bureaucratic.

05:06Competitors & 05:40 "you're better off sounding arrogant"

• Her answer: the category leader Generate Life Sciences neglects its low NPS, its branding, social, the doula channel, and the 97% of parents who don't know cord blood banking exists. She wrote that the competitor ViaCord is "completely disconnected from the modern consumer and complacent at its current margins" (relayed to her by a friend).
• She generalized her personal assumptions as if they were facts — it can read as arrogant, but she thinks it's the essence of pitching VCs and accelerators. "People are looking for a founder who will make their vision real. You have to come across as almost a narcissist to rally people around a mission."

06:28How long / 06:59 number of customers / 07:14 revenue / 07:34 the 'booked revenue' concept

• She quit her job in June and applied around October → about three months full time. Producing up to seven TikToks a day plus setting up the supply chain and managing provider relationships.
• Active customers: 13 pregnant women who had paid a deposit (not yet given birth, so not paid in full), and 6 completed stem cell collections.
• Revenue: "$200K in booked revenue." The deposit is $199 (as low as $20 during seasonal promotions). The reason that adds to $200K is that it's an eight-year monthly payment contract. She again emphasizes that seeing the forward vision without exaggerating is the mark of a great founder.

07:58Reapplying with the same or a different idea & 08:20 the first application (rejected)

• She pivoted because of a personal connection — her brother had cerebral palsy and could have benefited from cord blood (he passed away this year) — and because of healthcare's shift toward DTC.
• Her first application was an idea to improve the surrogacy space, 'nSGY' (similar to Nodal) → she eventually came back to cord blood banking.

08:50Why this idea / 09:19 the OG founder-led brand

• The inspiration was her mixed-race brother Andrew, who had cerebral palsy (the company name Anja comes from him) and couldn't find a cord blood match for his last treatment opportunity → the whole family became experts in the field.
• Evidence of demand: her cord blood TikToks drew over a million comments ("I'm four days too late, I had no idea this existed") that converted into paying customers.
• At the time, TikTok marketing and founder accounts were very new and novel — four years later "everyone has a founder account," so she's thinking about what's novel now.

09:44Competitors (the gap in understanding) & 10:02 business model & TAM

• Incumbents don't understand how the modern mother has changed — mothers live on Instagram, Facebook and Pinterest and trust creators, doulas and midwives over their own doctor (OB-GYNs say so themselves). The education and UX gaps are large too.
• Revenue: DTC e-commerce at 40% margin (actually closer to 60%). Prepaid or subscription. $3K–$7K total per customer (now $12K, up to $15K).
• TAM: 3.7M US births a year; if 30% (1.1M) banked with Anja that's a $5.5B+ opportunity, and just 20,000 customers is $100M ARR. The north star is 5% annual adoption (200,000 parents) and $1B ARR (justified by 10% adoption in parts of China and 30% in Singapore). Expansion plans include placenta banking (November), immune cells, genetic testing, and international.
• The lesson: draw the TAM big, $10B+ — you only ever capture a small slice, so the market has to be large from the start, and if you can't justify it, don't do it.

11:42Category & 12:04 building with no-code & 12:22 what's new

• Category: healthcare.
• She built everything herself with no-code — Zapier, Stripe, UMSO (a website builder), Churnbuster — "SaaS on top of SaaS."
• What's new: most parents don't know cord blood banking exists (80% of TikTok followers polled said they'd never heard of it). Even parents who do bank stop paying storage fees once the child is healthy at five, or can't remember the company's name (no brand voice). Anja reduces churn and spreads the message through content, brand and community — a space ripe for disruption by someone who understands content and marketing (her). (All of this came from actual user interviews.)

13:12Acquiring users & 14:01 healthcare-specific questions

• Not a chicken-and-egg problem. GTM runs through the 30,000+ TikTok community. By phase: phase 2 = social, ads, doulas, benefits packages, insurance, midwives, surrogacy, influencers and doctor partnerships (she researched all of them — it took three years); phase 3 = exclusive partnerships with large hospitals; phase 4 = retail placement at Babies R Us, Target and the like ("my company on a Target shelf" being the dream).
• Academic grounding: she linked numerous PubMed papers on cord and placental stem cell therapy. She also described the scientific basis and next development steps (a customer platform, a community of ~40) — though she only built the parent platform a year after YC (focusing first on optimizing customer acquisition).
• She never built her own lab (extremely expensive; following other founders' advice, she decided waiting until Series A/B was right).
• She exceeded her Demo Day goals (100+ partnerships, 50 bankings a month) — late in YC she hit 96 new customers in one month, all organic from TikTok.
• Regulation: no approval required (she had already talked to the FDA and others). She later obtained a California Department of Public Health and ICBBA blood bank license, with the lab aligned to AABB and FDA. The experimental basis: the FDA has approved cord blood for treating 85+ diseases, and cryopreservation has been regulated for 20 years.

16:47Logistics (entity, equity, financials)

• Incorporated as a C-Corp through Stripe Atlas. She had already raised a small pre-seed (which was hard because she knew nothing about fundraising — there's a separate YouTube video on it).
• Monthly spend of $25K (hiring expensive contractors — a rookie mistake), $323K in the bank, and with a seed raise dropping to ~$150K, a 12-month runway.

18:19How she found out about YC & 18:35 the 'hacks' she put in the application

• She went to Wellesley, a women's college, so she was disconnected from Silicon Valley — a few months before writing the application she didn't even know what YC was ("insane luck"). She learned a growth mindset watching founders at Ruth Health, Catch and others.
• For the "surprising or interesting thing you've discovered" question, she listed social growth hacks:
  • Put "DM @handle if you're interested" on a job posting → set the account to private so you have to follow to DM → follower growth. (She never actually did this one; she borrowed it from a friend who got rejected.)
  • Put your social handle in your dating app bio and set the location to a country where your ethnicity is common (being half Chinese, it worked well in China, Japan, Singapore and India).
  • Platform-by-platform strategy: LinkedIn = earnest Medium-style posts and milestones, Twitter = repurposing what performs, Instagram = hashtags plus your face, TikTok = her own TikTok hacks.
  • A tweet she linked ended up in YC's own growth presentation (a YC partner asked to use it) and her followers spiked — because she was early to founder accounts and TikTok growth.
• (She looks back on including all this with amused disbelief. "Can a girl not have a little fun?")

Closing — tips for the written application

• The final questions: no non-competes or IP agreements. What to know about the company = an anonymous mentor working in the cord blood industry made her realize this was "her life's calling" (kept out of the video to protect their identity).
• Overall tip: write concisely and think clearly about your idea. Follow Paul Graham's essays on writing — clear writing = clear thinking = clear marketing, product, roadmap and decision-making, which is exactly the evidence of what a founder needs.
• Very much a YC founder, she closes by doubling down on what works — the YC video performed best, so she'll make more YC content.

📌 Bottom line

• Kathryn Cross, a non-technical solo female founder, reads through the written YC application that got her cord blood banking startup Anja Health accepted, question by question, honestly marking what was true and what was exaggerated four years later.
• The running advice: ① even a little traction (waitlist, deposits, booked revenue) puts you ahead of the majority with none ② when pitching VCs, state your vision with conviction to the point of sounding arrogant rather than merely confident (assumptions stated as fact) ③ draw the TAM at $10B+ ④ concise, clear writing (the Paul Graham way) is the evidence of clear thinking.
• The practical insight: a $0-CAC TikTok founder account (2,000+ videos, 1M+ comments) that built a 6,000-person waitlist was the decisive factor — and the timing advantage mattered, because founder accounts and TikTok marketing were novel then.
• Her honest retrospective: solo founding really is hard and she'd want a partner next time; much of the ambition in the application went unexecuted (holding the lab until Series A/B, no international expansion); and she admits some of the 'social hacks' in the application were crowdsourced from others and never tried by her.