How the bundles of neurons in the brain control behavior remains an ongoing mystery and sexual behavior is among the biggest mysteries of all.

Not only do animals come in different shapes and sizes, but they all exhibit different behaviors as well - each species is born with its own unique set of innate behaviors but how they are controlled by the brain is not well understood.   Drosophila melanogaster , the 'fruit fly', is a big help in this sort of research because sex is a behavior the fruit fly does well. Their reproductive prowess has ensured their place throughout the world.
Breast cancer affects over 10% of women in Europe, the UK and USA, making it one of the most common cancers. Large population studies such as the Women’s Health Initiative and the Million Women Study have shown that progestins, synthetic sex hormones used in hormone replacement therapy (HRT) and in contraceptives, can increase the risk of breast cancers.

Medical researchers at the Institute of Molecular Biotechnology of the Austrian Academy of Sciences in Vienna have identified a key mechanism which allows these synthetic sex hormones to directly affect mammary cells.
A team of planet hunters has announced the discovery of an Earth-sized planet (three times our mass) orbiting nearby star Gliese 581 at a distance that places it squarely in the middle of the star's 'habitable zone', where liquid water could exist on the planet's surface.

If confirmed, this would be the most Earth-like exoplanet yet discovered among the nearly 500 known extrasolar planets - and the first strong case for a potentially habitable one.  To astronomers, a 'potentially habitable' planet is one that could sustain life, not necessarily one that humans would consider a nice place to live. Habitability depends on many factors, but liquid water and an atmosphere are among the most important.