Today's headlines from science and tech.

Below is today's selection of the most interesting science, health, and tech news reports. For analysis and commentary from around the Web, check out the  hot topics page. For Human Nature's takes on some of these stories, visit the blog. (I generally post the link first and write the blog entry later, so check back.) To add your own take, open or join a discussion thread in the Fray—and please link to the original story so others can participate intelligently in the conversation.

April 16

Growing "a human vascular system in mice" to test drugs
(Hellmut Augustin et al, Nature Methods)

A video-game headset that translates your real thoughts into virtual action
(Peter Sergo, Scientific American)

U.S. on track for 2 million knee and hip replacements per year
(Sunny Kim, Arthritis Care & Research)

Injection reactivates paralyzed limbs
(Prachi Patel-Predd, Technology Review)

A progress report on walking military robots – model #1 and model #2
(Larry Greenemeier, Scientific American)

"Many animals prefer to mate with their brothers, sisters and other relatives."
(Ewen Callaway, Science News)

Testosterone spray to boost women's sex lives works no better than placebo
(Andrew Humberstone et al, Annals of Internal Medicine)