Letters from the September 9, 2006, issue of Science News

Brother bother

If having biological older brothers correlates to homosexuality (“Gay Males’ Sibling Link: Men’s homosexuality tied to having older brothers,” SN: 7/1/06, p. 3), then we would expect that in the past, when families were larger, there would be a greater proportion of homosexuals. Is there any evidence for this?

Rick Norwood
Mountain Home, Tenn.

The article concludes with psychologist Daryl Bem inferring that male homosexuals are less aggressive than male heterosexuals. I thought that was part of the inaccurate stereotype of male homosexuals.

Jan McClure
Cardiff, Calif.

There’s no evidence on the question of homosexuality in large families of the past. Bem was referring to childhood traits.—B. Bower

Through a dino’s eyes

“Sight for ‘Saur Eyes: T. rex vision was among nature’s best” (SN: 7/1/06, p. 3) makes two questionable assertions. First, Tyrannosaurus rex might well have had excellent binocular vision and been a predator, but still have had a handicap for the detection of motion as my cats do. Second, when Thomas R. Holtz Jr. states that binocular vision “almost certainly was a predatory adaptation,” that puts us binocular hominids firmly among predators, while our dentition firmly disputes this.

Herb Windolf
Prescott, Ariz.

Whiff of danger?

If the estrogenic properties of lavender oil and tea tree oil are actually sufficient to produce these effects in young boys (“Lavender Revolution: Plant essences linked to enlarged breasts in boys,” SN: 7/1/06, p. 6), could they produce potentially more serious negative impacts on women with estrogen-positive breast cancer? I know that some oncologists recommend products containing tea tree oil to help relieve problems experienced by women undergoing chemotherapy.

George E. Burgoyne Jr.
Niles, Mich.

The tooth, the truth

Please check the picture in “Mexican find reveals ancient dental work ” (SN: 7/1/06, p. 13). The teeth shown are lower teeth.

Theodore Blinder
Havertown, Pa.

The story and caption misidentified the teeth that had been filed down 4,300 years ago. They were the bottom-front teeth, shown at left in the photo.—B. Bower