The 89th Annual Meeting of the American Association of Physical Anthropologists (2020)

How extreme are Kodhini’s twinning rates? A Geospatial and Temporal Look at Indian Twinning Rates


1Anthropology, University of South Florida, 2Precision Medicine, City of Hope National Medical Center, 3Department of Anthropology, Kannur University

April 16, 2020 , Platinum Ballroom Add to calendar

India’s -twin-birth-rate (TBR) has varied considerably within both physical location and temporal space, ranging from 10.5 and 12.44 per thousand. In the current work, we show that the so-called “twin town” of Kodhini in the Southern state of Kerala has experienced a twinning rate significantly higher than the background rate of Indian twinning. We also compare Kodhini’s rate with those of two other areas which have experienced an increase in twinning during the same time: in the Morena area of Madhya Pradesh and in Madurai, Tamil Nadu.

The population adjusted average twinning rate for India during the time period 1920-2015 was 10.65. In comparison, Madurai (Tamil Nadu) had a twinning rate of 56 percent from 1979-1982 (Thirumalaikolundusubramanian et al, 1986), and Morena (Madhya-Pradesh) had a twinning rate of 37.4 percent for the period 1963-1973 (Goswami, 1987). Kodinhi’s twinning rate increased from a low of 14% in the 1920s to a high of 61% in the 2000s (Raker et al. 2018). Although these twinning rates were highly significant when compared with the background twinning rate, Kodhini’s remains the highest of all.

Our work brings to light the importance of addressing the possible causes of the “twin epidemic” not only in Kodhini but also in these two other “twin foci”. Kodinhi is part of the Nannambra panchayat. Although it is a rural area, it is well connected by train and air. We wonder if during these decades these populations might have been exposed to insulin-like growth factors which may cause polyovulation.

Funded by an NSF EAGER award. Funded by the CAS Faculty Travel award. 

Slides/Poster (pdf)