Scientists say that every child a mother bears leaves some of their cells within her body–and that those cells can remain there for decades. Fetal microchimerism leaves Y chromosomes within the brains of women who have had sons and have been found in women who are in their nineties. We mothers have always known that our children change us forever–as it turns out this isn’t a maternal fantasy. 

I’m afflicted with geographical microchimerism myself. Every place I’ve ever lived in is embedded within me and will not go away. I never know when that adaptation is going to surface but when it does, it comes wrapped in a physical ache. Even the one city I really loathed, Penang, can submerge me in a feeling that is completely visceral, blood and bones and (in this case) nausea. Suddenly I’m back in a noodle shop, pushing my food away because the person next to me is spitting a piece of gristle onto the table or I’m sitting on a city bus trying not to smell the odor of unwashed hair.

I absorbed a city before I could talk. Although my parents left Manhattan before I was two, photos of New York could make me cry from the time I began to look at magazines. When we went back when I was six, the smell of bus exhaust and the screech of the subways were comforting and familiar. 

At any moment, I can find myself standing on a balcony, watching a Tucson sunrise or in Mendoza’s Bakery, buying cochitos. Or I can be on a Bangkok soi, feeling the warm breath of a baby elephant snuffling moisture into the palm of my hand; buying fabric in a crowded street market; feeling my temples throb after an hour of standing near the chainsaw engine of a riverboat and the piercing whistle of the boat boy. I’m visiting the community of feral cats or watching ballroom dancers in Beijing’s Beihai Park, searching for bookstores in Shenzhen, keeping an eye out for monkeys on a hillside path above Shatin. I’m sitting on a narrow bed in a closet-sized room in Chungking Mansions, with the fragrance of samosas wafting through some invisible entrance. And for a second or two, I stop breathing, caught in another dimension, another life.

I know if I went back to any of those places, what inhabits me would no longer be there. But it all lives inside me, bits and pieces that have colonized my cells and will never go away.

This odd gift of possession is like being haunted, a curse and a blessing that keeps me yearning, restless, and alive.