Here are some of the latest health and medical news developments, compiled by the editors of HealthDay:
Michael Jackson's Doctor Sentenced to 4 Years in Jail
Dr. Conrad Murray, physician to the late pop star Michael Jackson, was sentenced to 4 years in prison by a Los Angeles judge who called his actions a "disgrace to the medical profession," MSNBC.com reported.
After Jackson died in 2009 at age 50, investigators linked Jackson's frequent use of the drug propofol -- supplied to the singer by Murray -- as a possible contributor to his death.
According to MSNBC.com, Murray told police detectives that Jackson had been receiving nightly doses of propofol as a sleep aid, even though the drug is typically used only in hospitals and has not been sanctioned as a sleep treatment. Murray, who was contracted to be paid $150,000 a month for his services to Jackson, said he gave the pop star propofol on the day he died.
During sentencing, Judge Michael Pastor said Murray violated his obligation to his patient and "has absolutely no sense of remorse, absolutely no sense of fault, and is and remains dangerous" to the community.
Murray declined to testify at his trial, but in a documentary said that he does not consider himself guilty.
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Laptops' Wi-Fi May Damage Sperm: Study
A new study raises questions about whether using wi-fi on a laptop could harm a man's sperm.
Semen samples from 29 healthy donors were each divided into two pots. One pot was stored for four hours next to a laptop wirelessly connected to the Internet and the other pot was stored under identical conditions, but without the laptop, BBC News reported.
The researchers found that sperm in the pot next to the laptop were damaged. Their ability to swim was reduced and they had changes in the genetic code they carry. While heat can harm sperm, the researchers don't believe this damage was caused by heat from the laptop.
The study appears in the journal Fertility and Sterility.
Experts said this test was not conducted in a real-world setting and the findings should not cause men undue worry. However, they recommended more studies, BBC News reported.
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Scientists Spot Gene Linked to Sleep Duration
A gene that may explain why some people can function on a limited amount of sleep has been identified by German scientists.
They examined the genomes and sleep habits of more than 4,000 people in seven European countries and found that those with two copies of a particular variant of the ABCC9 gene generally slept less than those with two copies of a different version of the gene, ABC News reported.
The researchers also discovered that the ABCC9 gene controls sleep duration in fruit flies, which provides a clue about the gene's evolutionary age.
A study released in 2010 identified genetic differences that make some people sleepier during the day, even after they've a good night's sleep, ABC News reported.
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More U.S. Kids Being Exempted From Vaccinations
In eight states, more than 1 in 20 public school kindergarten students aren't getting all the vaccinations required for attendance and more than half of states have had at least a slight increase in the rate of parental exemptions over the past five years, according to an Associated Press analysis.
Rules for exemptions vary between states and can include medical, religious and even philosophical reasons.
In 2010-11, Alaska had the highest exemption rate (9 percent), followed by Colorado (7 percent), Minnesota (6.5 percent), Vermont and Washington (6 percent). Oregon, Michigan and Illinois were close behind. The lowest exemption rate was in Mississippi, the AP found.
Over five years, vaccine exemptions rose in more than half of states and the rate of exemptions increased by about 1.5 percent in 10 states.
The growing trend of parents seeking vaccination exemptions for their children has health officials concerned about possible outbreaks of diseases that had been all but eliminated, the AP reported.
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Chickenpox Shot Benefits More Than Babies: Study
The number of infant chickenpox cases in the United States fell nearly 90 percent between 1995 and 2008, a new study finds.
The findings show that the vaccine not only protects the child who is vaccinated, but also infants who come into contact with the child afterward, FoxNews.com reported.
The vaccine isn't given to children younger than 12 months, but they indirectly benefit when older children receive the vaccine, the researchers explained. Their study appears in the journal Pediatrics.
"It's not impossible for kids to have chickenpox after they've been vaccinated, even if they have two doses of vaccine. But the case is so mild and benign that it's much, much better," Dr. Elaine Schulte, a pediatrician at the Cleveland Clinic Children's Hospital, told FoxNews.com.
She was not involved in the study.
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