this is wrong and here is why:
occupying almost every part-time job and earning less money than the other sex, which does not work part-time, but full-time, does not contradict itself, it even seems like a rational conclusion, doesn’t it?
the earnings of self-employed people are dependent on the field they work in, as an example: a self-employed carpenter should earn more than the owner of a nail-salon, as carpentry is more dangerous and requires more training. as males tend to work more dangerous and therefore lucrative jobs it seems reasonable to earn more money while being self employed. i have to admit, i do not have a source here, but if required, i could surely find one.
as earning are less, so are retirement funds, exactly the same argument as above, just later on the time-scale of life.
male and female hygiene products are not identical in ingredients and research required for development and should therefore not cost the exact amount:
http://www.esquire.co.uk/magazine/article/6833/razors/
http://www.gillettevenus.com/en-us/how-to-shave/hair-removal-methods/dont-share-his-razor
http://www.allure.com/beauty-products/skin/2012/degree-dry-protection-deodorant-clean
http://www.allure.com/beauty-products/skin/deodorant/2012/degree-motion-sense-deodorant
https://www.pg.com/productsafety/msds/beauty_care/Gillette_Consumer_Products/Satin_Care_Sensitive_Shave_Gel_%2898946340%29.pdf
https://www.pg.com/productsafety/msds/beauty_care/Gillette_Consumer_Products/Gillette_Series_Shave_Gel_Sensitive_Skin_%2898651313%29.pdf
http://www.amazon.co.uk/Neutrogena-Fighter-Face-Moisturizer-Ounce/dp/B000FPTENY/ref=sr_1_2?ie=UTF8&qid=1430320024&sr=8-2&keywords=Neutrogena+Men%C2%AE+Age+Fighter+Face+Moisturizer+with+sunscreen+SPF+15
http://www.amazon.co.uk/Neutrogena-Healthy-Skin-Anti-Wrinkle-Cream/dp/B000052YOL/ref=pd_bxgy_d_text_y
http://www.drugstore.com/nivea-men-3-in-1-body-wash-energy/qxp185252?catid=184087
http://www.drugstore.com/nivea-happiness-moisturizing-body-wash/qxp210097
summary article explaining in detail, why the so called “pink tax” exists:
http://www.dailymail.co.uk/femail/article-2959383/Why-expensive-woman-called-pink-tax-women-pay-men-dry-cleaning-razors.html
if you do not want to pay more than a man for body wash as a woman, why not buy the one marketed to men? or why not buy the fucking cheapest washing-up liquid there is?
here is why: women generally (!) want more expensive things because it signifies high social standing and makes you the center of attention:
https://www.academia.edu/8088456/What_women_want_Creation_of_a_luxury_brand
http://www.luxuriousmagazine.com/2011/09/unlocking-the-mystery-of-why-women-love-to-buy-luxury-and-designer-handbags/
http://pss.sagepub.com/content/early/2013/11/22/0956797613502732.abstract
also a very informative and highly recommended video and channel, where i took all these informations from:
https://www.youtube.com/watch?v=8HEr8zmVEZQ