Here's a couple of pieces I found in short order:
https://www.jwatch.org/jw199110040000006/1991/10/04/heterose...
https://www.ncbi.nlm.nih.gov/pubmed/8420583
Here's a couple of pieces I found in short order:
https://www.jwatch.org/jw199110040000006/1991/10/04/heterose...
https://www.ncbi.nlm.nih.gov/pubmed/8420583