On 2014 Mar 01, David Mage commented:

The author is correct that infant asphyxia of overlaying by a co-sleeper has an equal risk for both males and females Williams FL, 2001. However, he is incorrect that the ratio of male to female infant deaths by SIDS is usually 2:1. When all SIDS studies are combined the male fraction goes to 0.61 corresponding to a male:female ratio of 3:2, not 2:1 Mage DT, 2004, Mage DT, 2014.

On 2014 Mar 01, David Mage commented:

The author is correct that infant asphyxia of overlaying by a co-sleeper has an equal risk for both males and females Williams FL, 2001. However, he is incorrect that the ratio of male to female infant deaths by SIDS is usually 2:1. When all SIDS studies are combined the male fraction goes to 0.61 corresponding to a male:female ratio of 3:2, not 2:1 Mage DT, 2004, Mage DT, 2014.