Sex matters, and I mean both the act between consenting adults and gender. There are many rules and conventions around both, and some are so different to what the western traveller is accustomed to at home, they may unknowingly break the law.
Homosexuality, despite what President Ahmadinejad said in 2007, DOES exist in Iran, although there's no popular "gay culture" as in the west. There's a small degree of openness in parts of Iran's upper classes, but in the general population acceptance is low, and state persecution is chronic.
The authorities are pretty serious about this one. The punishment for the "crime" of sodomy is death! Lesser "crimes", are punishable by lashing. If a man "kisses another with lust" – 60 lashes. It's up to the judgment of the local court, and fines and jail terms can be substituted, but men and women have been executed for being homosexual.
Controversially, transexuality is not illegal, in fact it is recognized by the state, and gender reassignment is endorsed. They'll even pay for the operation as a way to "cure" homosexuality. The state attitude to homosexuality, and the level of acceptance in Iranian society is contradictory and complicated – too complicated to get into here. But if you want to learn more try these links:
As a foreigner, unless you're shouting your "special love" from the rooftops, you're unlikely to fall foul of the law. The authorities kind of don't care what westerners get up to if they keep it to themselves. However, involving an Iranian could make it difficult for everyone.
In the end the law applies to Iranians and foreigners alike.
A blind eye is turned to heterosexual western couples. You should have no problems sharing a hostel or hotel room with your partner. It's unlikely you'll be asked, but if you are, just say you're married (as you would in any conservative society).
Again, once the door is closed no one will pay any attention to you. Traveller Mell blogged this a couple of years back:
"Although the laws are severe they really don't care what u do so long as u keep it away from Muslims. When I stayed in the hostel in Esfahan the dorm was mixed. We could have slept naked and had orgies in that dorm room for all they cared. Once I went up the stairs to our part of the hostel I cold take off the headscarf and even go to the shower with just a towel wrapped around me."
There's one blind eye but the other is wide open and watching… watching to make sure you don't "involve" Iranians or Muslims. If your partner could be Iranian or Muslim - and that might be as simple as dark-skinned or with an Arabic-sounding name – the authorities will start asking questions.
The easiest way to avoid this scrutiny is to get married. Send out the invitations now.
Not quite ready for that step? Then get a Muslim marriage certificate from a cleric at home. It says you're married and you've converted to Islam – but if you have your fingers crossed behind your back when you sign it doesn't count! Seriously, it's not a legal marriage in western countries unless you get a marriage license and certain words are said in a formal ceremony. (Does the phrase "by the power invested in me by the state of…" ring any bells?)
For non-Iranian women married (officially, legally) to an Iranian man, it's a whole different kettle of fish, and you need to read "The Ins and Outs of getting in and out of Iran".
To the western eye Iran is a "sexist" country. The women's rights and freedoms you consider "inalienable" may not apply here. And that is reflected in the attitude and actions of many, but not all, Iranian men.
Attitudes are changing - fast. In 2010, President Mahmoud Ahmadinejad went on state TV to tell men to stop harassing women. The President also removed the religious police from Tehran, prompting a new air of openness and relative freedom for women.
They're pushing their headscarves way back, and showing a lot of colour in their clothing. There's even hand-holding in public between young couples, and no one pays any attention.
If it still sounds a little repressive to you, try to remember, travel is about experiencing new cultures and different ways of life. Embrace the differences, respect them – for the time you are in Iran.
Here's Mell again with her experience:
"In public keep political or feminist comments bland. But don't let this put u off. There is a strong tradition of hospitality in Iran. People will welcome u and generally treat u like an honoured guest (apart from the weird attitudes most have towards women that is). If u are travelling with a man, people will rarely talk with u. All comments will be addressed to him. This is sexist for sure, but the upside is u will get to avoid answering the same questions that everybody in Iran will want to ask."
Women in Iran do not wear the veil or the burqa. A headscarf and a manteau (or a skirt) over trousers is all that's required, and showing your hair from under the scarf is acceptable, especially now the religious police have been removed from Tehran.
Of course, tube tops, bare arms and lots of leg is not acceptable. Cover up, but not too much, or you risk alienating the Iranian women who wear very stylish clothes.
They're well dressed, very stylish, and might regard overly-conservatively dressed western women as challenging the new freedoms they're enjoying.
Women can and do travel alone in Iran. Most report an enjoyable and trouble-free experience. A small number say harassment, leering, sleazy comments and groping almost made them regret going. Almost. They report the hassling is tiresome and annoying, but not dangerous and the prospect of it happening to you shouldn't put you off going to this amazing country.
The same thing doesn't happen if you travel with a male companion, but as Mell points out, then no one speaks directly to you.
Sex and sexual politics makes Iran a challenging destination. It's not for everyone, but through great effort comes great reward.