Is it socially acceptable for individuals to wear clothing typically associated with the opposite gender? What are some reasons for or against this practice?

Reasons against it? Basically,

2) Fashion crossdressers - some metrosexuals and most women fall into this category. Women in trousers – seen as a sexual and social aberration in 1900 – had become the norm by 2000.

Don’t do it in places where it’s illegal, like Russia.

Do people have to be a pastor to baptize?

8) Those forced into crossdressing. This category is included for completeness but barely seems to exist in real life today. It was however observed in the period 1850-1950 when boys were occasionally forced into girls' clothes as a punishment at school or in the home. It is a staple of fiction – to escape from danger (Some Like It Hot), to obtain a job (Tootsie, Mrs Doubtfire), or forced by a sadistic female relative (much transvestite erotic fiction).

There are many reasons. This can be broken down into the eight broad categories below, though most people only think of no.6:

c) Drag queens and Drag kings – an exaggerated satirical sub-section of the light entertainment field.

ESA’s Bug-Eyed Robot Telescope Just Spotted Its First Asteroid — And It Could Save the Planet - The Daily Galaxy

If you’re going to do it, do it 100% and do it well. You’ll enjoy it all the more and so will the people around you. It’s often good for a round of applause or a free drink.

a) In serious entertainment, actors playing a role. From Mark Rylance as Cleopatra or Judi Dench as Olivia to Antony Perkins in Psycho. Japanese Kabuki and Nō players. Sopranos singing "breeches" roles in opera.

7) Transsexuals – for many of them the cross-dressing is merely an incidental stage in their transition of identity. Once achieved, the wearing of the clothes of the other sex becomes the norm, and can no longer be called crossdressing.

Approximately 1.7 million air conditioners voluntarily recalled for potential mold exposure - ABC News

3) Fetish crossdressers - who use clothes as a substitute for, or an essential precursor to, sex. This is commonest among teenage boys, but usually disappears or develops into transvestism later. It is rarely seen in public, although the word "fetish" is often misapplied by those who should know better.

Ignore people who will quote their religion at you (unless it’s your religion too).

1) Occasional crossdressers - Hallowe'en, practical jokers, fancy dress parties, students' rags... etc.

Are today’s baseball pitchers faster than a few years ago, or is it that radar guns have improved and get the pitch speed as it is released rather than as it reaches the plate?

In Lancaster County, Pennsylvania or Salt Lake City it won’t be accepted. In Rio or Douarnenez at Mardi Gras it’s practically compulsory. (Seriously, I counted the men in skirts in a bar in Douarnenez: one in six.)

6) Transvestites – what most people first think of. For transvestites, crossdressing is an end in itself; motives many and various. For most, these go back to childhood or before birth and are obsessive.

d) Stunt doubles.

Scientists Stunned as Rare Phenomenon Emerges from Arctic’s Icy Depths - Indian Defence Review

4) Entertainers.

If it’s merely your sexual fetish — see 3) above — don’t do it in public. You’ll look ridiculous and possible offend decency laws.

b) In light entertainment: female impersonators/comedians; pantomime dames in British theatre.

‘King of the Hill’ voice actor Jonathan Joss is fatally shot in Texas - The Washington Post

Don’t do it unless you want to.

5) Other professionals: the occasional spy/undercover policeman/criminal in disguise. Gay prostitutes.

Socially acceptable? It depends on which bit of society you live in.

Lowering Blood Pressure May Cut Dementia Risk by Up to 15% - Neuroscience News