The reproductive biologist has patented a world first: a chemical contraceptive that kills sperm as well as the bacteria that cause sexually transmitted infections.

''If we could combine fertility regulation with protection against sexually transmitted disease, that would be a wonderful benefit to the population,'' Professor Aitken said.

The contraceptive is having safety trials and, for this research and more, Professor Aitken has been named the 2012 NSW Scientist of the Year.

The British-born biologist first became interested in the biology of sex after reading a book on elephant reproduction when he was a university student. He completed a PhD under the tutelage of the book's author, the reproductive biologist Professor Roger Short.

After a stint at the World Health Organisation in Geneva he realised ''the most important single thing to deal with on the surface of this planet is the unsustainable rate of population growth''.

''[It was then] I became very interested in developing improved forms of contraception.''

The University of Newcastle laureate professor also set himself the difficult task of developing the world's first biological male contraceptive. ''When you designing contraceptives for women, you're trying to stop the ovulation of one egg a month. Men produce 1000 spermatazoa a second,'' he said.

To top it off, Professor Aitken also studies the reproductive workings of domestic animals and has developed a non-surgical technique to sterilise cats and dogs, as well as produced a medium to improve the shelf life of the semen of horses and cattle.

But before he invented methods to prevent pregnancy, his research laboratory at the University of Edinburgh in the mid 1980s tackled the reverse issue: why about one in every 20 males were infertile.

Professor Aitken and his team found that too many free radicals in the body, a process known as oxidative stress, left sperm unable to fertilise an egg.

Since then, small studies suggest the problem can be remedied with antioxidants, found in fruit and vegetables, a treatment that may have enabled thousands of men to become fathers.

''Our understanding of male reproduction is probably 20 years behind our understanding of female reproduction,'' he said.

Professor Aitken hopes his award, one of eight NSW Science and Engineering Awards announced on Wednesday night, will highlight the contribution his research team has made in reproductive science.

He said his objective is to ''give people the choice to have exactly the number of children they want".

The NSW Deputy Premier, Andrew Stoner, said Professor Aitken's research also improved the efficiency of NSW's world-leading horse breeding industry, worth more than $4.2 billion each year.

Other awards went to Matthew England and Angela Moles, from the University of NSW, and Peter Robinson from the University of Sydney.