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  • Science has uncovered the origins of a lot of things over the centuries, but one question that's still on everyone's mind:

  • how did homosexuality evolve?

  • Hey guys, Tara here for Dnews - and over the past 2 years of doing this show,

  • we've covered a lot of scientific breakthroughs. Finding water on Mars, birth control for men, the relative usefulness of bras

  • but now, science may have solved one of its greatest mysteries

  • yet: how did homosexuality evolve?

  • Well, according to new research published in the journal Archives of Sexual Behavior,

  • it may have evolved in order to promote social bonding amongst humans.

  • This is the first study of its kind to find discrete evidence that our need to bond with others,

  • actually increases our openness to engaging in homosexual behavior.

  • For their study, a team of researchers from the University of Portsmouth looked at the

  • relationship between sexual attitudes and the hormone progesterone.

  • What they discovered, is that the more progesterone there is in a heterosexual woman's saliva,

  • the more open she is to the idea of engaging in homosexual behavior.

  • Likewise, heterosexual men who are subtly reminded about the importance of having male comrades.

  • Reported feeling more open towards engaging in homosexual behaviour - and that was particularly true for men with

  • higher levels of progesterone.

  • But what is it about this hormone that relates to all of this? Well, a bit of background -

  • progesterone is a steroid hormone, typically found in women's ovaries and men's adrenal glands.

  • In the same way that oxytocin is considered to be thelove hormone”,

  • progesterone is basically thefriendversion of that.

  • It's one of the main hormones responsible for caring and friendly behavior, which is why your levels of progesterone tend to rise

  • when you're having a close interaction with a friend.

  • Obviously, from an evolutionary standpoint, it's beneficial for humans to form social bonds.

  • So from that perspective, more progesterone in your body is a good a thing.

  • But then comes the topic of reproduction - which for humans, is basically the logical endpoint

  • of sexual behavior. Or at least, we think it is.

  • According to lead author Diana Fleischman, sexual behavior hasn't always been just about reproducing,

  • it's also about forming and maintaining social bonds.

  • And there's certainly evidence in other species, demonstrating that recreational sex isn't limited to just humans.

  • Great apes, for example, have historically engaged in homosexual behavior as a way of forging new friendships.

  • While we are on the topic of forging friendships,

  • I wanna veer off for a minute and let you guys know that today will officially be my last day on Dnews.

  • For those of you who follow me on Twitter, this shouldn't come as too much of a surprise -

  • since I did announce a few weeks ago that I would be leaving Discovery at the end of November.

  • But I just wanna say, for the record, what an absolute pleasure it has been working on this show -

  • it has been such an amazing experience

  • getting to host what I consider to be one of the best YouTube channels out there - no bias obviously.

  • Not to mention, being able to work alongside such an amazingly talented team, both on-screen

  • and behind the scenes, has been very inspiring.

  • I specially wanna thank you guys, our viewers, for welcoming me onto the show and into your homes.

  • you guys have been so wonderful to me these

  • past 8 months, and I will forever cherish my time with Dnews.

  • Of course, if you would like to keep up with me outside of the show, I encourage you to

  • follow me on Twitter, at

  • As always, if you guys have any questions, comments, fun memories, embarrassing moments

  • of me you'd like to reminisce about, please leave them in the comments below. Otherwise,

  • thanks for watching! I'll miss you guys.

Science has uncovered the origins of a lot of things over the centuries, but one question that's still on everyone's mind:

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Why Is There Homosexuality?

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    陳叔華 posted on 2016/06/11
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