Human tears contain a chemosignal
Science (2011) - Comments
pubmed: 21212322  doi: 10.1126/science.1198331  issn: 1095-9203  issn: 0036-8075 

Shani Gelstein, Yaara Yeshurun, Liron Rozenkrantz, Sagit Shushan, Idan Frumin, Yehudah Roth, Noam Sobel