When we launched CryptoKitties, we deliberately cultivated mystery and discovery around the CryptoKitties genome.

In the early days, players built tools to dive deeper into the breeding algorithm. They shared insights and theories about how breeding functioned, and they worked together as a community to crack the genome! Breeding is now a solved science: you can't control what kind of Kitty you'll breed, but you can use a breeding calculator to tell you the odds, or even suggest the best breeding pairs to buy to get that special Kitty you're craving.

Alas, the need for mystery is over. That's why we just released the source of the old geneScience smart contract for everyone to see. We're also releasing the new version today, so you can read it over before it goes live tomorrow.

We've tweaked the autobirth function

Until now, a vast network of "autobirthers" has been making sure that your Kitties are born on time. These midwives are important (because of super complex technical restrictions of smart contracts that we're not going to get into), and you can learn more about them on our active Discord community.

But they're also problematic. The first issue with autobirthers is that they're constantly competing with each other to help each Kitty give birth. The upside of that competition is it makes sure your Kitty gets born fast, but the downside is that it leads to network pollution. By having multiple people trying to submit the same transaction and competing for miners to choose them, autobirthers cause higher usage and higher gas prices.

The second problem is that, up until now, the breeding you've done hasn't supported the development of CryptoKitties. The majority of players assumed we made a slice from the birth of every Kitty, but we didn't.


That's why we've written in a rule that gives us first crack at being your midwife.

How your Kitty is born will not change, at all

We can't stress this enough. None of the breeding logic has been touched. How you breed new CryptoKitties, and the results, will not change.

So what's different?

Dapper Labs will be the first midwife of choice, paying Ethereum miners to process the geneScience contract. If we're too slow to claim first crack or network congestion has us down, the birth will still pass on to autobirthers, keeping the process decentralized and open.

What does this mean for you?

Hopefully you'll experience a smoother running network, especially during periods of intense breeding, thanks to reduced network pollution. And that's it — there won't be any changes.

We've put together a basic FAQ that covers everything we haven't talked about. Please track us down on Discord if you have any questions after you've read over both versions of the smart contract!


What does this mean for me? If you want to read the geneScience contracts (original, new), now you can! A lot of people have learned about smart contracts and best practices from reading the previously published CryptoKitties contracts, so we're happy to expand on that.

Does this mean I need a new breeding calculator? Not even a little bit.

Do the odds to pass on genes change at all? Nope.

Do the odds to mutate genes change at all? Naw.

Do my odds of hitting a Fancy change at all? No siree.

Will this have any impact on birth time for Kitties? Probably not, but even in the worst case scenario it would be less than two minutes (5 blocks) slower, since the autobirthers will be waiting to pick up any slack.

Does this mean CryptoKitties is centralized now? Nope. If for any reason we don't show up right away to serve as midwife, there will still be incentive for those veteran autobirthers to take over and make sure the job gets done quickly.

Will this affect the price of breeding? Not at all.

It won't get cheaper to breed? Sorry, no!

It won't more expensive to breed? Nope.

But now breeding supports the CryptoKitties team directly?

Got any other questions? Please drop by our Discord channel and ask away!