Hello! It has been about five weeks since we last spoke. Well, for me it has. For you, probably 24 hours. I write to you at the end of my first rotation, pediatrics. Ironic, yes? The universe, up to its old tricks. Give the childfree, middle-aged dude childcare as his first rotation.

As this is a trip through time, it’s fitting that our first stop involves children. They make the passage of time apparent, which it usually isn’t. The way an adult looks today is largely the way they will look tomorrow. The things an adult believed yesterday will probably be the things they believe tomorrow. With children, none of that is true.

They grow rapidly, changing dramatically from year to year well into their early 20s. Infants hit developmental milestones at a superhuman pace. It’s no wonder they cry a lot; I’m sure all that growth is uncomfortable. Children’s beliefs are fluid, easily changed by new information. Unlike adults, little of their ego is wrapped up in whatever belief system they adhere to at the moment. Kids are not just small adults. They are different creatures who happen to share some adult biology. It’s not surprising their care is specialized.

The patient populations at my rotation sites presented differently. Many of the Pakistani families I met lived in multigenerational households, with mothers coordinating the lives of several children and extended family members. Their young children were often remarkably healthy and bilingual.

At another site in Queens, I saw more childhood obesity among the Central and South American and Afro-Caribbean families we served. The reasons were not reducible to ethnicity or culture. They were tangled up in income, housing, food access, neighborhood design, parental work schedules, and the thousand other forces that medicine groups under the social determinants of health.

Social determinants of health are the conditions in which people are born, grow, live, work, and age. Researchers spend lifetimes working out why this or that disease appears here but not there. There are an enormous number of interacting variables: your genes—you can’t outrun them forever; food availability—processed foods seem to encourage overeating and obesity; pollution—higher rates of asthma are found near highway corridors, which generally run through less affluent neighborhoods; family stability—the lack of which can contribute to mental health difficulties; physical housing—older buildings may contain lead, which may effect cognitive development, or cockroaches, exposure to (meaning you inhale it) their poop can worsen asthma; and parental employment—money plays a huge role in health-related outcomes.

I suspect the list is actually endless. It’s enough to say that where you grow up and who your parents are enormously affects your long-term health. You control none of it but spend your life living with its consequences. This is only one of the many reasons this existence annoys me.

Wealthier parents stack the deck over their child’s lifetime through stronger schools, fresher food, safer neighborhoods, constant stimulation from toys, books, after-school activities—or grandparents—and better access to medical care through generous health insurance plans partially paid for by employers, who also allow paid sick leave to stay home with ill family members. While no single thing radically changes the trajectory of a child’s life, the cumulative effects of these little nudges become readily apparent over time. By 13 the gulf between the haves and have-nots is essentially insurmountable.

We’re back to time again.

Children experience time radically differently than adults. Their perception of it is slower. To us, a single day feels considerably shorter than it does to them. We experience fewer unique milestones as routine comes to dominate our adult years. One author calculated that our perceived lifetime is already two-thirds over by the time we reach our early 30s. Childhood summers seemed endless. Now entire years disappear with alarming efficiency. By the time someone reaches advanced age, I am not certain they discern individual days anymore.

But we are here, at the beginning.

Many of my young patients were on Medicaid. Even viewed with cold economic pragmatism, ensuring children have healthcare coverage makes extraordinary financial sense to a nation. Adult medicine often involves trying to undo the accumulated consequences of the past, and it’s expensive. Pediatric medicine offers a chance to shape the future for a fraction the cost. Small interventions now can produce enormous differences decades later. A healthy child may become a healthy adult who contributes meaningfully to a family, a community, and another generation.

I like working with children. I feel time moving when I am around them. It’s not an unpleasant sensation, like feeling a gentle breeze on your face on an otherwise still day. Ah, there you are, I think, before it fades away.

See you in five weeks. Or tomorrow, depending on your perspective.

News Events of the Rotation

Date	Major event
Sept. 8–9	Youth protests toppled Nepal’s government. Demonstrations against corruption and a social media ban met a deadly crackdown. Prime Minister K. P. Sharma Oli resigned on September 9.
Sept. 9	Israel struck Hamas leaders in Doha, Qatar. The attack expanded the conflict into a country serving as a mediator in Gaza ceasefire negotiations.
Sept. 10	Charlie Kirk was assassinated while speaking at Utah Valley University, becoming a major national story about political violence.
Sept. 10	Russian drones entered Polish airspace, prompting Polish and allied aircraft to respond and intensifying concerns about the Ukraine war spilling into NATO territory.
Sept. 17–23	ABC suspended and then reinstated Jimmy Kimmel’s show following his comments about Kirk’s killing, fueling a national debate over speech and political pressure on broadcasters.
Sept. 21–22	The U.K., Canada, Australia and France recognized Palestinian statehood, a major diplomatic shift during the Gaza war and U.N. General Assembly meetings.
Sept. 22	Trump and RFK Jr. made a major autism announcement, promoting a possible association with prenatal Tylenol exposure and discussing leucovorin. Medical organizations pushed back, emphasizing that research had not established that acetaminophen causes autism