Recumbent cycling

A few questions have been asked about recumbent cycling as the Greenspeed GT3 and Longbikes recumbent tandem have appeared on the scene.

Here are some links taken from the Fuse Recumbents web site here:
http://www.fuse-recumbents.com.au/reviewsandlinks.html#med

Medical Research Pertaining to Recumbent Cycling

Following are some links that discuss some of the physiological aspects of cycling in general and recumbents in specific. Note that in some cases listed a "recumbent bike" is in fact a recumbent stationary exercise bike, and as such the conclusions drawn may not totally match the reality of on-road cycling. Nevertheless, the broad direction of the conclusion should hold.

The recumbent position may be beneficial in reducing loads on the anterior cruciate ligament in the knee while cycling:
http://www.ncbi.nlm.nih.gov/pubmed/15133932?dopt=Abstract

Cycling on a tandem machine produces lower physiological stress than a single rider machine:
http://bjsm.bmj.com/cgi/content/full/37/1/50

Recumbent cycles may be more beneficial than conventional cycles for some diabetic riders:
http://www.ncbi.nlm.nih.gov/pubmed/11926324?dopt=Abstract

Is there any difference in penile blood flow during cycling in an upright versus a reclining position?:
http://www.ncbi.nlm.nih.gov/pubmed/11464064?dopt=Abstract

"The Vicious Cycling" - a discussion of some of the urological issues of upright cyclists that recumbents avoid:
http://www.ncbi.nlm.nih.gov/pubmed/15716187?dopt=Abstract