Names like Grant or Greg are thoroughly associated with males, while Isabelle and Antoinette are clearly associated with females. Other names, however, are significantly more androgynous. If you were to receive an email from an unknown Sam, Morgan, or Jamie, you wouldn’t be sure of the sender’s gender. What makes a name clearly suitable for one gender or the other? Although some names “sound” decidedly masculine or feminine, most of our perception of what makes a name suitable for only one particular gender stems from how consistently that name is only applied to one gender but not the other. In other words, boys’ names aren’t especially masculine sounding, they just happen to be given almost exclusively to boys. Unisex names, therefore, lack gender markers because the name is assigned to boys and girls with roughly equal frequency. With this reasoning in mind, this post’s question can be rephrased as “what name is assigned to boys and girls most evenly?”
The US Social Security Administration (SSA) publishes a large database that provides an answer to our question. The data consists of over 100,000 different names that have been given to babies born in the US from 1880 through 2012. Yearly counts are reported by gender for each name, totaling about 330 million births. For privacy considerations, the SSA omits name counts for years with fewer than 5 occurrences.
We assigned each name a “unisex score,” calculated as the degree to which a name’s counts by gender approximated a “50-50 split.” For example, if a name was given to 100,000 boys since 1880 and 100,000 girls in the same time period, the name would have a perfect (i.e. the highest) unisex score because the split is exactly even. For the purposes of this analysis, we limited our attention to names with total counts above 100,000, meaning that the name needed to occur on average 752 times per year since 1880. We limited our investigation to popular names so highly obscure ones with perfect unisex scores (e.g. “Ammer” or “Elmi”) wouldn’t clutter our results.
Based on the analysis above, the most unisex name in US history is Riley. Since 1880, 154,000 people have been named Riley in the United States. Of these people, 46.6% have been female and 53.4% have been male, resulting in an extremely high unisex score for the name. The top five most androgynous names by this same metric are:
- Riley, difference in gender split: 53.4% – 46.6% = 6.8%
- Jackie, 7.2%
- Jaime, 13.3%
- Casey, 18.3%
- Jessie, 20.4%
The popularity of each of these names waxes and wanes over time. The charts the the right show counts for the most unisex names over time, with girls and boys represented by the red and blue lines, respectively. While unisex names’ popularity fluctuates over time, the names are popular for girls and boys simultaneously. If the popularity by gender were to occur separately (i.e. not concurrently), gender confusion would be more easily avoided. For example, until about 1940, Leslie was almost exclusively assigned to males, but has since become mostly a female name. Therefore, if we hear about a Leslie born before 1940, our guess should be that the person is male, but we should reverse our guess for younger Leslies.
Unisex scores can also be used in reverse to identify the most lopsided names (i.e. the most masculine or feminine names). The top 5 most masculine names are:
- Ethan, difference in gender split: 99.65%
- Grant, 99.65%
- Liam, 99.65%
- Jake, 99.62%
- Wyatt, 99.58%
The top 5 most feminine names are:
- Angelina, 99.79%
- Lily, 99.78%
- Isabella, 99.76%
- Katelyn, 99.75%
- Ava, 99.75%