Originally Posted by hystrix

Only way to tell the difference is to look at the gene product, protein and such, to see which gene is expressed where and when.

Originally Posted by Andy n Claire

this title is geting me thinking lol
"going to find dudette then to bed !

Originally Posted by hystrix

We know where and when actually. In gonads during the gonad formation and also during puberty. which gene doesn't really matter because both males and females have them in the case of TSD species. That's why it's hard to determine the sex of juveniles. There is not much difference in the gene expression (thus amount of hormones) between male and female before puberty (except during gonad formation inside the egg).

Originally Posted by hystrix

Those are secondary sexual characteristics, Ed. Other more familiar examples are fat deposition, musculature, body hair... Think of humans, men are usually larger, more hair, more muscular, females can have those characteristics if given large doses of testosterone over a long period of time.

Like I stated before, female body produces a small amount of testosterone, but not enough to have those male specific characteristics. Secondary sexual characteristics are controlled by sex hormones produced in the gonads, the production of sex hormones, in turn, is controlled by differential gene expression. Every cell in a body, except for haploid sex cells (eggs and sperms) contain the same set of DNA. The difference is, which ones are on or off at the given time.

Animals with CSD have different set of genes between male and female, but animals with TSD have the same set of genes, male or female. You cannot determine which gene is on or off by just looking at the sequence.