It is demonstrated that a form of Rubio de Francia’s hitherto unresolved Littlewood-Paley Type Conjecture from the year 1985 is valid for the weighted-(L^{2}left( {mathbb {R}}right) ) space corresponding to any even (A_{1}left( {mathbb {R}}right) ) weight. Otherwise expressed, we show that if (omega ) is any even (A_{1}left( {mathbb {R}}right) ) weight, C is an (A_{1}left( {mathbb {R}}right) ) weight constant for (omega ), ( fin ) (L^{2}left( {mathbb {R}},omega left( tright) dtright) ), and (left{ J_{k}right} _{kge 1}) is any finite or infinite sequence of disjoint intervals of ({mathbb {R}}), then the following estimate holds for the corresponding Littlewood-Paley Type square function defined by (left{ S_{J_{k}}left( fright) right} _{kge 1})(where the symbol (S_{_{J_{k}} }) denotes the indicated partial sum projection for the context of ({mathbb {R}})):
$$begin{aligned} left| left{ sum limits _{kge 1}left| S_{J_{k}}left( fright) right| ^{2}right} ^{1/2}right| _{L^{2}left( {mathbb {R}},omega left( tright) dtright) }le 2^{5}C^{1/2}left| fright| _{L^{2}left( {mathbb {R}},omega ^*left( tright) dtright) }, end{aligned}$$where (omega ^*) is the decreasing rearrangement of (omega ). A corollary of this even (A_{1}left( {mathbb {R}}right) )-weighted theorem is obtained which provides a related variant thereof in the setting of any (not necessarily even) (A_{1}left( {mathbb {R}}right) ) weight.