Couples who split chores equally DON'T have less sex. The previously posted study was based on outdated data.

Here's the abstract of the study by scientists from Cornell University published in the Journal of Marriage and Family:

Although contemporary couples increasingly express preferences for egalitarian unions, previous research has suggested that sexual intimacy decreases when routine housework is shared. Yet this research was conducted on data that are decades old. To update this work, the authors compared data from the 2006 Marital and Relationship Survey (MARS) and Wave 2 of the National Survey of Families and Households (NSFH2), collected in 1992–1994. The results indicated change in the association between housework arrangements and sexual intimacy across surveys. Although egalitarian arrangements were associated with lower sexual frequency compared to conventional arrangements in the NSFH2, no such difference was found in the MARS. In fact, reported sexual frequency increased across surveys among egalitarian couples only. In addition, how housework was arranged mattered more for sexual satisfaction among MARS couples than NSFH2 couples. These changes appear to result from the increasing role of perceived equity as a mechanism linking the division of housework to sex.

Although at this point MARS is decades old as well, it reflects a shift towards egalitarianism and suggests that traditionalism isn't inherently more beneficial in this context.

Here's the link to the original thread posted a few days ago.