The answer is, of course, the penis.

And while this has been a topic of discussion in recent years, a new study suggests that a penis can have a better chance of making a donor.

In a new paper, published in the American Journal of Men’s Health, researchers at the University of Southern California compared the sperm profiles of men and women who had received penis transplants to those of healthy men and healthy women.

“We found that the quality of the sperm was lower in men than in women,” said Dr. James Dominguez, one of the paper’s authors.

“We don’t think this is a random, biological phenomenon.”

“It was a very strong effect,” said Domingez, who was not involved in the research.

“It’s not just because there are more males,” said researcher David Bresnahan, who is also a professor at USC’s Department of Plastic Surgery.

“This was a strong effect for both men and for women.”

A penis with more cells, less fluid, and lower levels of inflammation can increase the chances of success.

The results of the study suggest that the penis with the highest chance of success might be the one with the most cells and the lowest level of fluid.

This would help ensure a man has enough cells to create a healthy donor.

“If we can increase sperm quality, we can help a lot,” Domingoz said.

“The male’s quality is not the only factor that determines success.

The quality of a woman’s fertility, too, is important.””

The question we want to answer is: What does this mean for the donor?

What’s the chance that a woman will have a good chance?” asked Dr. Robert A. Zimring, a professor of obstetrics and gynecology at the Icahn School of Medicine at Mount Sinai.”

There are a lot of variables,” he said.

For instance, the donor’s body size, the amount of fluid, the level of inflammation, and other factors will affect the success of the transplant.

The new study is one of several that has examined the potential of male reproductive organs for creating successful transplants.

In 2011, researchers from the National Institutes of Health funded a study that looked at the sperm quality of sperm donors who had donated their semen to healthy women, and found that sperm quality was significantly higher in men who had been given penises than in those who had not.

The researchers said this could help explain why men who have had penises are more likely to be able to give birth.

The current study is the first to look at the same issue in men and found there was a significant correlation between the sperm’s quality and the chance of getting a transplant.

“We’re really trying to figure out what the difference is,” Drominguez said.