By Peter Berton

NEW YORK – You know the times they are a-changin’ when a crusty, conservative publication like The Wall Street Journal publishes a “Market Watch” article titled “Five Ways to Invest in Sex.”

One way the Journal advises readers to cash in on sex is by collecting and then selling vintage Playboy magazines — the older and less-loved, the better. Apparently, an eBay user sold a December 1953 Playboy with Marilyn Monroe on the cover for $39,000. The Journal also cited Dab Wade of the UK memorabilia firm Paul Fraser Collectibles saying “issues in good condition from 1954 … generally run in the three figures.”

WSJ make-money-from-sex tip No. 2: Invest in condom manufacturers. Thanks to developing markets in third-world countries, global condom sales are expected to rise by 46 percent over the next six years, hitting $6.5 billion by 2020. The Journal noted Trojan brand owner Church & Dwight has seen its stock price “more than double over the past five years.”

The Journal then qualified its conclusion by noting the Trojan manufacturer also makes kitty litter, antiperspirant and home pregnancy tests.

Tip No. 3: Put money into strip clubs. Specifically, the WSJ likes Rick’s Cabaret International, a publicly traded gentlemen’s club operator with 43 U.S. locations. According to the Journal, the company’s stock price “is up roughly 25 percent in the past year.”

Tip No. 4: Cash in on Cialis and Viagra. All that money spent by Baby Boomers on erectile dysfunction treatment drugs has to be making someone rich, right? Too true, the WSJ reports: Eli Lilly earned $215 billion from Cialis sales in 2013 — up 12 percent from 2012 — while Viagra made $1.88 billion for Pfizer.

Tip No. 5: Invest in really old porn. For instance, only 1,000 first edition copies of Lady Chatterley’s Lover were published in 1928, all privately by author D.H. Lawrence and all signed by the author. The estimated value of a single copy stands anywhere from $7,000 to $30,000.

So there you have it: Five ways to make money from sex, courtesy of the formerly stuffy Wall Street Journal. Talk about unexpected.