When students in Stanford University’s Introduction to Bioengineering course sit for their final exams, the first question that they have to answer is about our ability to write DNA.

Scientists have fully sequenced the genomes of humans, trees, octopuses, bacteria, and thousands of other species. But it may soon become possible to not just read large genomes but also to write them—synthesizing them from scratch. “Imagine a music synthesizer with only four keys,” said Stanford professor Drew Endy to the audience at the Aspen Ideas Festival, which is co-hosted by the Aspen Institute and The Atlantic. Each represents one of the four building blocks of DNA—A, C, G, and T. Press the keys in sequence and you can print out whatever stretch of DNA you like.

In 2010, one group did this for a bacterium with an exceptionally tiny genome, crafting all million or so letters of its DNA and implanting it into a hollow cell. Another team is part-way through writing the more complex genome of baker’s yeast, with 12 million letters. The human genome is 300 times bigger, and as I reported last month, others are trying to build the technology that will allow them to create genomes of this size.

For now, that’s prohibitively expensive, but it won’t always be that way. In 2003, it cost 4 dollars to press one of the keys on Endy’s hypothetical synthesizer. This month, it costs just two cents—a 200-fold decrease in price in just 14 years. In the same time frame, the cost of tuition at Stanford has doubled, and is now around $50,000. Given all of that, the first question that Stanford’s budding bioengineers get is this:

At what point will the cost of printing DNA to create a human equal the cost of teaching a student in Stanford?

And the answer is: 19 years from today.

There are a lot of assumptions built into that answer. It will take a lot of technological advances to print the complex genomes of humans and to keep the costs falling at the same pace as they have done. But bearing those assumptions in mind, the problem is a mathematical one, and the students are graded on their ability to solve it. But the follow-up question is a little more complicated:

If you and your future partner are planning to have kids, would you start saving money for college tuition, or for printing the genome of your offspring?

The question tends to split students down the line, says Endy. About 60 percent say that printing a genome is wrong, and flies against what it means to be a parent. They prize the special nature of education and would opt to save for the tuition. But around 40 percent of the class will say that the value of education may change in the future, and if genetic technology becomes mature, and allows them to secure advantages for them and their lineage, they might as well do that.

There is clearly no right answer to the second question, and students are graded on their reasoning rather than their conclusion. But when both questions are considered together, they suggest, Endy says, that “in the order of a human generation, we’ll have to face possibilities that are much stranger than what we’re prepared for.”