So you want to change your sexual orientation...

This is for sure a problem. However, I believe it's possible to solve it in a more pragmatic manner. Theoretically, if I'm right, parents are no longer legally obliged to provide for the child after it is 18 years old. But most young people continue their education in some way and aren't yet ready to work full-time and earn all their money themselves. So in praxis most young people continue living by their parents' money until they are over 20 years old.
I also believe it's not a good solution to give people all rights at the same time, children are ready for many things while still being too young for others. For example the right to vote - people say children wouldn't understand the parties' programs, but do adults really understand them? Conscious voters are in fact not more than 50% of all adults. (Another solution that seems very interesting for me - we keep 18 as legal voting age, but every person who is at least 14 years old can try passing a test that would prove his or her understanding of how politics work and if s/he does, s/he is allowed to vote despite not being 18.) At the same time I don't think that children should be allowed to try psychoactives without their parents' permission, for me the ideal solution is 18 years minimum to be allowed to buy tobacco or marijuana and 20 years for other psychoactives, including alcohol.
And as for the starting topic - maybe... I'm generally unenthusiastic about "experimentation" in this area. I won't forbid anyone any kind of consensual sex, but I will also never say that having sex with someone you don't love is right.

i'm not so convinced this drug will never reach humans -- it doesn't seem like that big a step to me from the rats to the people. sexual identity is definitely composed of many factors, but pure orientation -- meaning only what's likely to sexually arouse someone -- is much more biological, it seems to me. i can see how a drug might be able to change just that part of it. and once a drug is created, especially one that alters consciousness in some way, people *will* experiment with it.

i personally think it's a fantastic and very hopeful development. if it were easy to change orientation and you knew it would be just as easy to change it back, i think a lot of people would try it, and that could only increase the general level of tolerance and acceptance of all orientations. i'd like to see even more specific drugs developed, that could change your turnons in a variety of ways, just to be able to explore all kinds of ways of being and really throw yourself into each one!

i'm interested in your comment about children's rights. generally speaking i'm totally with you on that, but i also wonder: at the point when children receive more rights, 15 or whatever, does that also mean that at that point the parents have less responsibility to care for/provide for the child?

Well, myself I'm a student of Gender Studies, so I'm exetremely interested in gender/queer subjects. But I'm not sure that research on fruit flies is that significant. People are not fruit flies, human sexual orientation is about much more than just sex drive. All previous attempts to change people's sexual orientation have been succesful only in bringing the "patients" into depression and even leading them to suicide. (Actually in Poland there are still people attempting "conversion therapy", but this is really a homophobic country. Lately there has been a report on a Catholic activist doing such "therapy" - she doesn't have any psychological or medical education.)
I clearly believe this is not the parents' right to determine their children's sexual orientation and I generally believe parents should have a bit LESS rights over their children (I would for example support the right to vote and various other rights, including the right to decide about medical treatment, starting from the age of 15 or even less) because nobody can OWN a human being, parents are not owners of their children.
Such a drug is dangerous because there are already pamphlets out there saying that gays want to seduce all young boys and convert them into gays - much in the style of the "Protocols of the Elders of Zion". The availability of such a drug could intensify such fears. But I don't think any research on humans will be allowed. It's likely to remain just a curiosity that it's possible to switch sexual orientation in fruit flies - no ethical commitee will allow clinical trials on humans because of possible very negative consequences and because homosexuality is no longer treated as something that should be "cured". Of course some possibility that the drug could "leak" out of the laboratories does exist, but not unless the researchers are committed homophobes.
Let's wait if some urban legends pop out - the government spiking water supply? ;)