In this combination photo, Actor Orlando Bloom (L) attends a meeting with city officials in Sarajevo August 12, 2008, and British actor Daniel Craig waves to Japanese fans as he arrives at the Japanese premiere for his latest James Bond movie "Quantum of Solace" in Tokyo November 25, 2008. REUTERS/Damir Sagolj/Issei Kato

LONDON (Reuters) - Why do some women’s hearts race over the feminine features of Orlando Bloom while others are more attracted to macho men like Daniel Craig?

Being on the contraceptive pill could be the reason, according to British scientists.

Researchers said that women whose hormones are chemically controlled are less likely to seek out muscular, rugged men.

Whereas, they say, ovulating women not on the pill “exhibit a preference for more masculine features, are particularly attracted to men showing dominance and male-male competitiveness and prefer partners who are genetically dissimilar to themselves.”

Women on the pill tend to pick more effeminate men who look like themselves. This could lead to problems conceiving, according to the study conducted at the University of Sheffield.

“There is evidence that genetic similarity between couples might be linked with infertility,” said the study, published in the Trends in Ecology and Evolution medical journal.

The birth control pill could also throw a spanner in the works of the laws of natural attraction as it prevents women giving off monthly fertility signals believed to be subtly alluring to men.

“Ovulation is associated with a profound shift in some female physical characteristics, behaviors and perceptions related to male attraction,” the report said.